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@article{faucris.121361504,
abstract = {The fracture behavior of the unpoled 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO(3) relaxor ferroelectric was investigated. Previous studies indicated that a metastable ferroelectric long-range order can be induced by mechanical stresses, which could lead to a crack tip process zone and increasing crack resistance during crack growth. Crack propagation in compact tension samples yielded a constant crack resistance as function of crack length. This is consistent with ex situ x-ray diffraction experiments, where a remanent induced process zone on the fracture surface could not be detected. We suggest the very high transformation stress, determined via macroscopic stress-strain measurements, is responsible for the absence of toughening. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Voegler, M. and Daniels, J. E. and Webber, Kyle Grant and Roedel, J.},
doi = {10.1016/j.scriptamat.2017.04.023},
faupublication = {yes},
journal = {Scripta Materialia},
keywords = {Relaxor;Fracture toughness;Lead-free;NBT-BT;Ferroelectric},
pages = {115-119},
peerreviewed = {Yes},
title = {{Absence} of toughening behavior in 0.94({Na1}/{2Bi1}/2){TiO3}-0.{06BaTiO}(3) relaxor ceramic},
volume = {136},
year = {2017}
}
@article{faucris.111505944,
abstract = {The field-driven phase transformation behavior of relaxor ferroelectric single crystal PZN-xPT is discontinuous and displays well-defined forward and reverse coercive fields, whereas the same transformation in PMN-xPT is nearly continuous and occurs over a range of field levels. In analogy to the broad Curie range in relaxor ferroelectrics arising from property fluctuations at the nanometer length scale, the continuous field-driven phase transformations in PMN-xPT are modeled as a step-like series of discontinuous transformations associated with similar spatial property fluctuations. An increase in the applied field gradually increases the volume fraction of the new phase at the expense of the old phase, resulting in a continuous transition between phases. The model simulation produces excellent agreement with the measured material response of < 011 > cut PMN-0.32PT single crystals under conditions of cooperative stress and electric field loading. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Webber, Kyle Grant and Robinson, Harold C. and Rossetti, George A. and Lynch, Christopher S.},
doi = {10.1016/j.actamat.2008.02.006},
faupublication = {no},
journal = {Acta Materialia},
keywords = {dielectrics;electroceramics;perovskites;ferroelectricity.;piezoelectricity},
pages = {2744-2749},
peerreviewed = {Yes},
title = {{A} distributed step-like switching model of the continuous field-driven phase transformations observed in {PMN}-{xPT} relaxor ferroelectric single crystals},
volume = {56},
year = {2008}
}
@article{faucris.252099651,
abstract = {While lead-free (Li,Na,K)NbO3 piezoceramics have a high Curie temperature (TC > 400 °C) and an excellent piezoelectric constant (d33 > 200 pC/N), the process window regarding the sintering temperature and dwelling time is narrow. Inappropriate sintering conditions can induce the volatilization of A-site alkali ions, leading to a deterioration in dielectric and piezoelectric properties. However, the effect of alkali volatilization on the ferroelastic properties is still uncertain. In this study, (Li,Na,K)NbO3 piezoceramics were deliberately exposed to the sintering temperature for varying times to compare the susceptibility of the effect of alkali volatilization on the ferroelastic properties and compared to changes in the ferroelectric and ferroelastic and dielectric properties.},
author = {Nishiyama, Hiroshi and Martin, Alexander and Hatano, Keiichi and Kishimoto, Sumiaki and Sasaki, Nobuhiro and Webber, Kyle Grant and Kakimoto, Ken Ichi},
doi = {10.2109/jcersj2.20201},
faupublication = {yes},
journal = {Journal of the Ceramic Society of Japan},
keywords = {Alkali volatilization; Electrical hardening; Ferroelasticity; Lead-free piezoceramics},
note = {CRIS-Team Scopus Importer:2021-03-19},
pages = {127-134},
peerreviewed = {Yes},
title = {{Alkali} volatilization of ({Li},{Na},{K}){NbO3}-based piezoceramics and large-field electrical and mechanical properties},
volume = {129},
year = {2021}
}
@article{faucris.119706224,
abstract = {This work presents the design, development, and characterization of unimorphtype laminated piezoelectric actuators. The actuators consist of a piezoelectric lead zirconate titanate (PZT) layer sandwiched between unidirectional Kevlar 49 and epoxy composite layers. Differential thermal expansion during processing places the ceramic plate in a state of residual compression and results in a curved actuator. Modified classical lamination theory (MCLT) (modified to include piezoelectricity) was used to design the actuators. Three layups were fabricated and characterized: [90/PZT/90/0], [90(2)/PZT/90/0(2)], and [90(3)/PZT/90/0(3)]. Results were compared to a commercially available unimorph-type actuator made from layers of metal, adhesive, and piezoelectric material. The classical lamination theory predictions were in good agreement with the measured response of the PZT composite actuators and provide a useful design tool for these actuators.},
author = {Webber, Kyle Grant and Hopkinson, David P. and Lynch, Christopher S.},
doi = {10.1177/1045389X06056059},
faupublication = {no},
journal = {Journal of Intelligent Material Systems and Structures},
keywords = {piezoelectric actuator;unimorph;composite;classical lamination theory;ECLIPSE actuators},
month = {Jan},
pages = {29-34},
peerreviewed = {Yes},
title = {{Application} of a classical lamination theory model to the design of piezoelectric composite unimorph actuators},
volume = {17},
year = {2006}
}
@article{faucris.299899472,
abstract = {The electromechanical behavior and phase transition of lead-free piezoelectric Bi1/2K1/2TiO3 (BKT) can be modified without changing the processing parameters, composition, or microstructure through post-densification thermal treatment. Although this provides a method to control the disorder and, thereby, the thermal stability, the role of annealing atmosphere remains not well understood. In this work, solid-state processed BKT was annealed with varying cooling rates (5 K/min to 0.1 K/min) and atmospheres (air, oxygen, nitrogen) in order to investigate influence on the functional properties. Crystal structure analysis revealed an enhanced evaporation of volatile constituents of BKT ceramics, namely Bi3+ and K+ after the annealing in oxygen atmosphere, leading to decreasing properties, i.e., dielectric response. Also, a suppression of the relaxor-to-ferroelectric transition is observed in the dielectric response at lower cooling rates, demonstrating the influence of the atmosphere and cooling rate during thermal process in BKT. The findings are linked to structural changes respectively defect content (A-sites vacancies) and chemical homogeneity of A-site cations in BKT atmospherically annealed samples.},
author = {Eyoum, Gina and Gadelmawla, Ahmed and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2023.03.002},
faupublication = {yes},
journal = {Ceramics International},
keywords = {Dielectric properties; Perovskites BKT; Post-annealing},
note = {CRIS-Team Scopus Importer:2023-05-12},
peerreviewed = {Yes},
title = {{Atmosphere} and cooling rate effect on the dielectric behavior of the lead-free piezoelectric {Bi1}/{2K1}/{2TiO3}},
year = {2023}
}
@article{faucris.217794433,
abstract = {This work demonstrates the successful deposition of bioactive glass (BG)45S5 coatings on various metallic and ceramic substrates at room temperature under low vacuum condition by using aerosol deposition (AD). This room temperature and particle impact consolidation-based deposition method enabled us to deposit well-adhered and dense BG coatings directly on metallic and ceramic substrates. In vitro tests with human osteoblast-like cells on substrates with a 45S5 BG coating demonstrated high cell activity on the surfaces. All tested materials exhibited high in vitro biocompatibility as no inhibition in cell proliferation could be observed. The utilization of AD process for achieving non-crystalline BG coatings is promising for practical bio-medical applications, e.g., bioactive coatings on bioinert metallic and ceramic substrates.},
author = {Eckstein, Udo and Detsch, Rainer and Khansur, Neamul Hayet and Brehl, Martin and Deisinger, Ulrike and de Ligny, Dominique and Boccaccini, Aldo R. and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2019.04.197},
faupublication = {yes},
journal = {Ceramics International},
keywords = {Aerosol deposition; Bioactive coatings; Bioactive glasses; In vitro},
note = {CRIS-Team Scopus Importer:2019-05-17},
peerreviewed = {Yes},
title = {{Bioactive} glass coating using aerosol deposition},
year = {2019}
}
@article{faucris.281401390,
abstract = {In this study, in situ stress-dependent Raman and Brillouin spectroscopy has been performed on polycrystalline 0.93(Na1/2Bi1/2)TiO3-0.07BaTiO3 (NBT-7BT). Brillouin scattering revealed stress-dependent changes in the elastic properties around the onset stress as well as the appearance of a transversal acoustic wave mode at elevated stress levels, which is understood to be due to the formation of long-range order. These data were compared with additional Raman scattering measurements, ex situ x-ray diffraction, and macroscopic stress-strain behavior, which revealed analogous changes in the apparent crystallographic structure and ferroelectric order in the vicinity of the onset and coercive stresses.},
author = {Martin, Alexander and Brehl, Martin and Khansur, Neamul Hayet and Werr, Ferdinand and de Ligny, Dominique and Webber, Kyle Grant},
doi = {10.1016/j.actamat.2022.118218},
faupublication = {yes},
journal = {Acta Materialia},
note = {CRIS-Team Scopus Importer:2022-09-09},
peerreviewed = {Yes},
title = {{Brillouin} spectroscopy study of the stress-induced ferroelectric order in lead-free relaxor 0.93({Na1}/{2Bi1}/2){TiO3}-0.{07BaTiO3} ceramics},
volume = {238},
year = {2022}
}
@article{faucris.111506164,
abstract = {Pb(Mg(1/3)Nb(2/3))O(3)-0.32(PbTiO(3)), PMN-0.32PT, single crystals have been characterized under combined stress and electric field loading [McLaughlin EA, Liu T, Lynch CS. Relaxor ferroelectric PMN-32%PT crystals under stress and electric field loading: I-32 mode measurements. Acta Mater 2004;52:3849, McLaughlin EA, Liu T, Lynch CS. Relaxor ferroelectric PMN-32%PT crystals under stress, electric field and temperature loading: II-33-mode measurements. Acta Mater 2005;53:4001] [1-3]. This approach is extended to PMN-0.26PT single crystals to explore the effect of composition on field driven phase transformations and to PMN-0.32PT ceramic specimens to compare with polycrystalline behavior. Electric displacement and strain were measured as a function of combinations of stress and both unipolar and bipolar electric fields. The single-crystal results indicate that compositions further from the morphotropic phase boundary require higher driving forces for field induced phase transformations. Evidence of these transformations is not apparent in the results from the ceramic specimens. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Webber, Kyle Grant and Zuo, Ruzhong and Lynch, Christopher S.},
doi = {10.1016/j.actamat.2007.11.025},
faupublication = {no},
journal = {Acta Materialia},
keywords = {relaxor;phase transformation;ferroelectric;constitutive behavior;single-crystal},
pages = {1219-1227},
peerreviewed = {Yes},
title = {{Ceramic} and single-crystal (1-x){PMN}-{xPT} constitutive behavior under combined stress and electric field loading},
volume = {56},
year = {2008}
}
@article{faucris.248087855,
abstract = {Aerosol deposition (AD) is a promising additive manufacturing method to fabricate low-cost, scalable films at room temperature, but has not been considered for semiconductor processing, so far. The successful preparation of cesium lead tribromide (CsPbBr3) perovskite films on interdigitated indium tin oxide (ITO) electrodes by means of AD is reported here. The 20–35 µm thick layers are dense and have good adhesion to the substrate. The orthorhombic Pnma crystal structure of the precursor powder was retained during the deposition process with no signs of defect formation. The formation of electronic defects by photoluminescence spectroscopy is investigated and found slightly increased carrier recombination from defect sites for AD films compared to the powder. A nonuniform defect distribution across the layer, presumably induced by the impact of the semiconducting grains on the hard substrate surface, is revealed. The opto-electronic properties of AD processed semiconducting films is further tested by electrical measurements and confirmed good semiconducting properties and high responsivity for the films. These results demonstrate that AD processing of metal halide perovskites is possible for opto-electronic device manufacturing on 3D surfaces. It is believed that this work paves the way for the fabrication of previously unimaginable opto-electronic devices by additive manufacturing.},
author = {These, Albert and Khansur, Neamul Hayet and Almora, Osbel and Luer, Larry and Matt, Gebhard and Eckstein, Udo and Barabash, Anastasiia and Osvet, Andres and Webber, Kyle Grant and Brabec, Christoph},
doi = {10.1002/aelm.202001165},
faupublication = {yes},
journal = {Advanced Electronic Materials},
keywords = {aerosol deposition; hysteresis; impedance spectroscopy; inorganic perovskites; photoluminescence spectroscopy},
note = {CRIS-Team Scopus Importer:2021-01-22},
peerreviewed = {Yes},
title = {{Characterization} of {Aerosol} {Deposited} {Cesium} {Lead} {Tribromide} {Perovskite} {Films} on {Interdigited} {ITO} {Electrodes}},
year = {2021}
}
@article{faucris.111565344,
abstract = {Bismuth sodium titanatebarium titanate [(1-x)(Na1/2Bi1/2)TiO3-xBaTiO3, NBT-100xBT] is one of the most well studied lead-free piezoelectric materials due in large part to the high field-induced strain attainable in compositions near the morphotropic phase boundary (x = 0.06). The BaTiO3-rich side of the phase diagram, however, has not yet been as comprehensively studied, although it might be important for piezoelectric and positive temperature coefficient ceramic applications. In this work, we present a thorough study of BaTiO3-rich NBT-100xBT by ferroelastic measurements, dielectric permittivity, X-ray diffraction, and Raman spectroscopy. We show that the high-temperature mechanical behavior, i.e., above the Curie temperature, TC, is influenced by local disorder, which appears also in pure BT. On the other hand, in NBT-100xBT (x<1.0), lattice distortion, i.e., tetragonality, increases, and this impacts both the mechanical and dielectric properties. This increase in lattice distortion upon chemical substitution is counterintuitive by merely reasoning on the ionic size, and is due to the change in the A-O bond character induced by the Bi3+ electron lone pair, as indicated by Raman spectroscopy. (C) 2015 AIP Publishing LLC.},
author = {Deluca, Marco and Picht, Gunnar and Hoffmann, Michael J. and Rechtenbach, Annett and Toepfer, Joerg and Schader, Florian H. and Webber, Kyle Grant},
doi = {10.1063/1.4916784},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Chemical} and structural effects on the high-temperature mechanical behavior of (1-x)({Na1}/{2Bi1}/2){TiO3}-{xBaTiO}(3) ceramics},
volume = {117},
year = {2015}
}
@article{faucris.111507264,
abstract = {The ferroelastic properties of a hard acceptor-doped lead zirconate titanate (PZT) ceramic are investigated between room temperature and 300 degrees C. Comparison with a soft PZT shows that acceptor doping has a stronger influence on mechanically induced domain switching than on switching caused by electric fields. A quantitative analysis of spontaneous and remanent strain and polarization indicates that poling in the soft material is dominated by 180 degrees domain processes, while non-180 degrees processes dominate the strain behavior. If the mechanical load exceeds a threshold level, the "hardening" effect of the acceptor doping vanishes, and hard and soft materials behave identically. The results are discussed based on the defect dipole model and the charge drift model for hardening and aging in acceptor-doped ferroelectric ceramics.},
author = {Marsilius, Mie and Webber, Kyle Grant and Aulbach, Emil and Granzow, Torsten},
doi = {10.1111/j.1551-2916.2010.03801.x},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {2850-2856},
peerreviewed = {Yes},
title = {{Comparison} of the {Temperature}-{Dependent} {Ferroelastic} {Behavior} of {Hard} and {Soft} {Lead} {Zirconate} {Titanate} {Ceramics}},
volume = {93},
year = {2010}
}
@article{faucris.111474264,
abstract = {Polycrystalline (1-x)BiFeO3-xBaTiO(3) (0.11 <= x <= 0.5) ceramics have been prepared by the solid-state reaction method to investigate their phase structure, dielectric, ferroelectric, and field-induced strain behaviors. The phase was found to change from rhombohedral in BiFeO3-rich compositions to pseudocubic at a BaTiO3 content of x=0.33. The room-temperature dielectric permittivity increased with increasing BaTiO3 content regardless of phase structure, except for a small dielectric permittivity peak additionally observed at x=0.33. The (1-x)BiFeO3-xBaTiO(3) solid solutions displayed a maximum in permittivity at temperatures (T-m) above 300 degrees C in the compositional range of 0.2 <= x <= 0.5. The frequency dependence of high-temperature dielectric properties suggests that BiFeO3-BaTiO3 is a relaxor ferroelectric. Normal ferroelectric loops and large electric field-induced strains were observed for the BiFeO3-BaTiO3 ceramics. The BiFeO3-BaTiO3 shows a promising candidate for high temperature ferroelectric applications. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.},
author = {Zhang, Hailong and Jo, Wook and Wang, Ke and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2013.09.020},
faupublication = {no},
journal = {Ceramics International},
keywords = {Powders: solid state reaction;Dielectric properties;Ferroelectric properties;BaTiO3 and titanates},
pages = {4759-4765},
peerreviewed = {Yes},
title = {{Compositional} dependence of dielectric and ferroelectric properties in {BiFeO3}-{BaTiO3} solid solutions},
volume = {40},
year = {2014}
}
@article{faucris.123034824,
abstract = {The compositional dependent fracture behavior of soft PZT (Pb0.99Ba0.01(Zr1-xTix)(0.98)Nb0.02O3) ceramics in the vicinity of the morphotropic phase boundary was characterized using compact-tension specimens. The compositions with 0.40 <= x <= 0.55 displayed an increasing fracture resistance with crack extension (R-curve behavior). It was observed that the rhombohedral composition and the compositions near the morphotropic phase boundary showed the largest toughness enhancement. R-curve behavior was found to be influenced by the ferroelastic coercive stress, saturated remanent strain, and elastic modulus, which were experimentally measured for each composition. X-ray diffraction measurements were performed and compared to the fracture results to investigate the impact of phase and lattice distortion on ferroelastic toughening behavior.},
author = {Seo, Yo-Han and Bencan, Andreja and Koruza, Jurij and Malic, Barbara and Kosec, Marija and Webber, Kyle Grant},
doi = {10.1111/j.1551-2916.2011.04889.x},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {4419-4425},
peerreviewed = {Yes},
title = {{Compositional} {Dependence} of {R}-curve {Behavior} in {Soft} {Pb}({Zr1}-{xTix}){O}-3 {Ceramics}},
volume = {94},
year = {2011}
}
@article{faucris.111577444,
abstract = {
The design of core–shell materials affords additional degrees of freedom to tailor functional properties as compared to solid solution counterparts. Although to date most of the work in core–shell materials has focused on dielectrics, piezoelectric core– shell ceramics may gain similar interest. Generalities of core–shell functional ceramics features are addressed in this work. A model system, Bi1/2Na1/2TiO3–SrTiO3, is introduced to discuss struc- ture–property relationships. We demonstrate that this system fea- tures a core–shell microstructure for the composition corresponding to 25 at.% Sr. The material is studied by means of macroscopic functional properties and in situ structural character- ization techniques at different length scales, such as X-ray diffrac- tion, transmission electron microscopy, and Raman spectroscopy. The evolution of the core–shell with field and temperature deter- mines its functional properties. The high strain of the system, ~0.3% at 4 kV/mm, is due to an electric-field-induced phase tran- sition of the core and shell. Upon field removal the core remains in a poled state, whereas the shell is characterized by a reversible transformation. The reversibility of the phase transition of shells and associated switching are key features in the observed giant strain. Dielectric anomalies are found to be related to changes in oxygen octahedral tilting angles within the core and shell.
},
author = {Acosta, Matias and Schmitt, Ljubomira A. and Molina-Luna, Leopoldo and Scherrer, Michael C. and Brilz, Michael and Webber, Kyle Grant and Deluca, Marco and Kleebe, Hans-Joachim and Rödel, Jürgen and Donner, Wolfgang},
doi = {10.1111/jace.13853},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
pages = {3405-3422},
peerreviewed = {Yes},
title = {{Core}–{Shell} {Lead}–{Free} {Piezoelectric} {Ceramics}: {Current} {Status} and {Advanced} {Characterization} of the {Bi1}/{2Na1}/{2TiO3}–{SrTiO3} {System}},
volume = {98},
year = {2015}
}
@article{faucris.261540512,
abstract = {Evolution of spectroscopic properties of a soda–lime silicate glass with different thermal history and under applied uniaxial stress was investigated using Raman and Brillouin spectroscopies as well as Nd3+ photoluminescence techniques. Samples of soda–lime silicate with a cooling rate from 6 × 10−4 to 650 K/min were prepared either by controlled cooling from the melt using a differential scanning calorimeter or by a conventional annealing procedure. Uniaxial stress effects in a range from 0 to −1.3 GPa were investigated in situ by compression of the glass cylinders. The spectroscopic observations of rearrangements in the network structure were related to the set cooling rates or the applied uniaxial stress to calculate an interrelated set of calibrations. Comparing the results from Raman and Brillouin spectroscopy with Nd3+ photoluminescence analysis, we find a linear dependence that can be used to identify uniaxial stress and cooling rate in any given combination concurrently. The interrelated calibrations and linear dependence models are established and evaluated, and equations relating the change of glass network due to effects of cooling rate or uniaxial stress are given.},
author = {Bergler, Michael and Cvecek, Kristian and Werr, Ferdinand and Veber, Alexander and Schreiner, Julia and Eckstein, Udo and Webber, Kyle Grant and Schmidt, Michael and de Ligny, Dominique},
doi = {10.3390/ma14133584},
faupublication = {yes},
journal = {Materials},
keywords = {Brillouin spectroscopy; Cooling rate; Fictive temperature; Glass structure; Raman spectroscopy; Soda–lime silicate glass; Uniaxial stress; Window glass},
note = {CRIS-Team Scopus Importer:2021-07-16},
peerreviewed = {Yes},
title = {{Coupling} raman, brillouin and nd3+ photo luminescence spectroscopy to distinguish the effect of uniaxial stress from cooling rate on soda-lime silicate glass},
volume = {14},
year = {2021}
}
@article{faucris.111485704,
abstract = {The room temperature crack growth resistance behavior of polycrystalline lanthanum-doped bismuth ferrite-lead titanate was characterized with disc compact-tension specimens. Through lanthanum doping the tetragonality can be adjusted from 1.01 to 1.10, while retaining a mixed phase system. Experimental measurements show changes in toughening behavior with increasing c/a ratio. Fracture results are discussed in conjunction with macroscopic ferroelastic constitutive behavior and stress-dependent neutron diffraction measurements to elucidate the role of a mixed phase system with heterogeneous mechanical properties. Additional X-ray diffraction measurements were performed to determine the effect of possible crack-tip stress-induced phase transformations on R-curve behavior. (C) 2012 Elsevier Ltd. All rights reserved.},
author = {Leist, Thorsten and Broetz, Joachim and Seo, Yo-Han and Cheng, Shumeng and Webber, Kyle Grant},
doi = {10.1016/j.engfracmech.2012.08.008},
faupublication = {no},
journal = {Engineering Fracture Mechanics},
keywords = {Ferroelastic toughening;Fracture of ferroelectrics;Ferroelasticity;Process zone;Ferroelastic toughening;Fracture of ferroelectrics;Ferroelasticity;Process zone},
pages = {267-275},
peerreviewed = {Yes},
title = {{Crack} growth resistance behavior of lanthanum doped bismuth ferrite-lead titanate: {Effect} of tetragonality and mixed phase crystal structures},
volume = {96},
year = {2012}
}
@article{faucris.314583432,
abstract = {This work explores the creep behavior of polycrystalline 0.91(Na1/2Bi1/2)TiO3-0.06BaTiO3-0.03K0.5Na0.5NbO3 under constant electric fields. It reveals intriguing time-dependent variations in both polarization and strain response, which can be attributed to a transformation from the relaxor state to a long-range ferroelectric order. Meanwhile, bulk volume resistivity values are obtained to eliminate the influence of leakage current on the polarization assessment. The findings provide valuable insights into the creep behavior of lead-free relaxor ferroelectrics, laying a solid foundation for enhancing the performance and reliability of piezoactuators.},
author = {Chen, Di and Ayrikyan, Azatuhi and Chu, Xiangcheng and Kamlah, Marc and Webber, Kyle Grant},
doi = {10.1088/1361-6463/ad090e},
faupublication = {yes},
journal = {Journal of Physics D: Applied Physics},
keywords = {constant electric field loading; creep behavior; lead-free piezoceramic},
note = {CRIS-Team Scopus Importer:2023-12-01},
peerreviewed = {Yes},
title = {{Creep} in 0.91({Na1}/{2Bi1}/2){TiO3}-0.{06BaTiO3}-0.{03K0}.{5Na0}.{5NbO3} lead-free piezoceramic under constant electric field loads},
volume = {57},
year = {2024}
}
@article{faucris.111486804,
abstract = {Strain response of polycrystalline barium titanate (BaTiO3) was investigated under high unipolar electric field (0 to 4 kV/mm) and compressive stress (0 to 400 MPa) in the temperature range from 25 to 160 degrees C. In the vicinity of the Curie point (T-C), nonlinear and hysteretic strain-electric field and strain-stress constitutive behaviors were observed, persisting above T-C where they correspond to the well-known electric field induced double loop polarization behavior. Analogous to the electrical double loops, the mechanical (strain-stress) hysteretic behavior above T-C is caused by a stress induced phase transition from the paraelectric/paraelastic to ferroelectric/ferroelastic phase; the electro-elastic (strain-electric field) hysteresis is similarly caused by an electric field induced phase transition. The stress and electric field at which transitions occur increase linearly with increasing temperature, exhibiting critical behavior typical for the first order phase transitions. The temperature limit for the induced phase transition extends up to 12 degrees C over T-C. Results are discussed in relation to the Landau-Ginzburg-Devonshire free energy expansion. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767059]},
author = {Picht, Gunnar and Webber, Kyle Grant and Zhang, Yining and Kungl, Hans and Damjanovic, Dragan and Hoffmann, Michael J.},
doi = {10.1063/1.4767059},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Critical} mechanical and electrical transition behavior of {BaTiO3}: {The} observation of mechanical double loop behavior},
volume = {112},
year = {2012}
}
@article{faucris.111497364,
abstract = {Ferroelastic toughening in Pb(Zr1-xTix)O3 (PZT) ceramics can be augmented by phase transformation toughening through the inclusion of partially stabilized TZ (PZTZrO2). In order to deconvolve both these toughening modes, cubic Pb1-yLay(Zr1-xTix)O3 (PLZT) with and without zirconia (PLZTZrO2) was characterized. R curve and stressstrain behavior yielded a quantification of strong toughening and a lack for switching propensity that could be contrasted to PZT and zirconia-toughened PZT. A clear path for toughening of PZT for future application is therefore provided.},
author = {Seo, Yo-Han and Webber, Kyle Grant and Bencan, Andreja and Koruza, Jurij and Malic, Barbara and Kosec, Marija and Rödel, Jürgen},
doi = {10.1111/jace.12007},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {3713-3715},
peerreviewed = {Yes},
title = {{Deconvolving} {Ferroelastic} and {Phase} {Transformation} {Toughening} in {Pb}({Zr1}-{xTix}){O}-3 and {Pb1}-{yLay}({Zr1}-{xTix}){O}-3},
volume = {95},
year = {2012}
}
@article{faucris.283170683,
abstract = {Powder aerosol deposited (PAD) ceramic thick films are a promising candidate for applications in energy storage and energy harvesting. The room-temperature deposition process allows for integration of ceramic films on low-melting substrates, such as stainless steel and polymers, without sintering. Despite this, the dielectric and electromechanical properties vastly differ from bulk ceramics due to internal residual stresses, oxygen defects, and the nano-grained microstructure associated with the deposition process. Although thermal annealing can improve macroscopic properties, precise control of the thermal expansion mismatch between the film and the substrate is required to avoid delamination and film cracking. In this study, we present a method to determine the actual thermal expansion of the film based on the fabrication of freestanding PAD films. Utilizing freestanding films, we demonstrate that dopants and processing conditions such as the carrier gas species directly influence oxygen defects thus modulating the unit cell volume and the conductivity of the oxide film. This is found to be crucial to attain improved dielectric properties within a moderate temperature environment (500 °C) preserving the benefits of the room-temperature deposition process. Additional densification mechanisms are investigated with transmission electron microscopy, scanning electron microscopy, and X-ray microtomography.},
author = {Eckstein, Udo and Khansur, Neamul Hayet and Urushihara, Daisuke and Asaka, Toru and Kakimoto, Ken ichi and Fey, Tobias and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2022.07.241},
faupublication = {yes},
journal = {Ceramics International},
keywords = {Energy storage; Functional ceramic thick films; Powder aerosol deposition; Structural characterization},
note = {CRIS-Team Scopus Importer:2022-10-14},
pages = {33082-33091},
peerreviewed = {Yes},
title = {{Defect} modulated dielectric properties in powder aerosol deposited ceramic thick films},
volume = {48},
year = {2022}
}
@article{faucris.107164684,
author = {Froemling, Till and Steiner, Sebastian and Ayrikyan, Azatuhi and Bremecker, Daniel and Duerrschnabel, Michael and Molina-Luna, Leopoldo and Kleebe, Hans-Joachim and Hutter, Herbert and Webber, Kyle Grant and Acosta, Matias},
doi = {10.1039/c7tc03975a},
faupublication = {yes},
journal = {Journal of Materials Chemistry C},
pages = {738-744},
peerreviewed = {Yes},
title = {{Designing} properties of ({Na1}/{2Bi}: {X}){TiO3}-based materials through {A}-site non-stoichiometry},
volume = {6},
year = {2018}
}
@article{faucris.120410444,
abstract = {Piezoelectric multilayer actuators are technologically important devices used in numerous positioning and force generation applications. During operation, the actuator displacement and force are nonlinearly coupled to the applied electric field, which is often ignored during material characterization. In this study, a novel experimental arrangement is presented that acts like a virtual linear spring, allowing for characterization of the full operational range as a function of applied electric field as well as the true blocking force and impedance matching system stiffness. The macroscopic measurements are contrasted to previous experimental techniques, providing insight into the effect of path dependence on the blocking force.},
author = {Webber, Kyle Grant and Franzbach, Daniel J. and Koruza, Jurij},
doi = {10.1111/jace.13024},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {2842-2849},
peerreviewed = {Yes},
title = {{Determination} of the {True} {Operational} {Range} of a {Piezoelectric} {Actuator}},
volume = {97},
year = {2014}
}
@article{faucris.230920148,
abstract = {Aerosol deposition (AD) is a dynamic loading process that can be envisioned as a shock wave loading, necessitating the consideration of the elastic/plastic response of solid materials. Due to the dynamic nature of this process, however, experimental determination of the local pressures during the deposition process is difficult. This work addresses this by investigating the compression and subsequent structure modification of a silicate glass after room-temperature AD on a silicate glass substrate with Raman spectroscopy. Clear structural changes in the short- and middle-range order of the silicate glass were observed, both as intertetrahedral angle distribution and as ring statistic. Therefore, the AD induced permanent densification of the glass, equivalent, in a hydrostatic approximation, to a minimal pressure of 10.5 ± 1.5 GPa during the film deposition process. Furthermore, the analysis of the Nd3+ photoluminescence of the 4F3/2 − 4I9/2 transition provided complementary information on the glass network modifications occurring during film formation. More than a pure hydrostatic densification, the AD seems to present a very intense shear deformation. This work opens up the perspective of evaluating the mechanical response of film-substrate and of the particles themselves, and provides critical information on the mechanisms responsible for the AD film formation.},
author = {Cicconi, Maria Rita and Khansur, Neamul Hayet and Eckstein, Udo and Werr, Ferdinand and Webber, Kyle Grant and de Ligny, Dominique},
doi = {10.1111/jace.16947},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
keywords = {deformation; densification; photoluminescence; Raman spectroscopy; room-temperature aerosol deposition},
note = {CRIS-Team Scopus Importer:2019-12-31},
pages = {2443-2452},
peerreviewed = {Yes},
title = {{Determining} the local pressure during aerosol deposition using glass memory},
volume = {103},
year = {2020}
}
@article{faucris.108967804,
abstract = {High piezoelectricity of (K,Na)NbO3 (KNN) lead-free materials benefits from a polymorphic phase transition (PPT) around room temperature, but its temperature sensitivity has been a bottleneck impeding their applications. It is found that good thermal stability can be achieved in CaZrO3-modified KNN lead-free piezoceramics, in which the normalized strain d(33)* almost keeps constant from room temperature up to 140 degrees C. In situ synchrotron X-ray diffraction experiments combined with permitivity measurements disclose the occurrence of a new phase transformation under an electrical field, which extends the transition range between tetragonal and orthorhombic phases. It is revealed that such an electrically enhanced diffused PPT contributed to the boosted thermal stability of KNN-based lead-free piezoceramics with high piezoelectricity. The present approach based on phase engineering should also be effective in endowing other lead-free piezoelectrics with high piezoelectricity and good temperature stability.},
author = {Yao, Fang-Zhou and Wang, Ke and Jo, Wook and Webber, Kyle Grant and Comyn, Timothy P. and Ding, Jing-Xuan and Xu, Ben and Cheng, Li-Qian and Zheng, Mu-Peng and Hou, Yu-Dong and Li, Jing-Feng},
doi = {10.1002/adfm.201504256},
faupublication = {yes},
journal = {Advanced Functional Materials},
keywords = {lead-free;niobate;phase transition;piezoelectric;temperature stability},
pages = {1217-1224},
peerreviewed = {Yes},
title = {{Diffused} {Phase} {Transition} {Boosts} {Thermal} {Stability} of {High}-{Performance} {Lead}-{Free} {Piezoelectrics}},
volume = {26},
year = {2016}
}
@article{faucris.217636863,
abstract = {In this work, the creep behavior of (Na1/2Bi1/2) TiO3-0.07BaTiO(3) was characterized as a function of bias stress up to -500 MPa, revealing the time-dependence of the stress-induced relaxor-to-ferroelectric long-range order transformation. Creep strain was observed across a range of applied compressive stress levels, in particular at stresses approximately 50% above the critical coercive stress, indicating the significant time-dependence of the transformation on the long-range ferroelectric order. The macroscopic behavior is discussed in conjunction with ex situ piezoresponse force microscopy measurements that directly show the formation of ferroelectric domains in mechanically loaded relaxor ferroelectrics. Published under license by AIP Publishing.},
author = {Martin, Alexander and Ursic, Hana and Rojac, Tadej and Webber, Kyle Grant},
doi = {10.1063/1.5084255},
faupublication = {yes},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Direct} observation of the stress-induced domain structure in lead-free ({Na1}/{2Bi1}/2) {TiO3}-based ceramics},
volume = {114},
year = {2019}
}
@article{faucris.211503367,
abstract = {In this work, the creep behavior of (Na1/2Bi1/2) TiO3-0.07BaTiO(3) was characterized as a function of bias stress up to -500 MPa, revealing the time-dependence of the stress-induced relaxor-to-ferroelectric long-range order transformation. Creep strain was observed across a range of applied compressive stress levels, in particular at stresses approximately 50% above the critical coercive stress, indicating the significant time-dependence of the transformation on the long-range ferroelectric order. The macroscopic behavior is discussed in conjunction with ex situ piezoresponse force microscopy measurements that directly show the formation of ferroelectric domains in mechanically loaded relaxor ferroelectrics. Published under license by AIP Publishing.},
author = {Martin, Alexander and Ursic, Hana and Rojac, Tadej and Webber, Kyle Grant},
doi = {10.1063/1.5084255},
faupublication = {yes},
journal = {Applied Physics Letters},
note = {CRIS-Team WoS Importer:2019-02-21},
peerreviewed = {Yes},
title = {{Direct} observation of the stress-induced domain structure in lead-free ({Na1}/{2Bi1}/2) {TiO3}-based ceramics},
volume = {114},
year = {2019}
}
@article{faucris.122254704,
abstract = {Almost free-standing single crystal mesoscale and nanoscale dots of ferroelectric BaTiO3 have been made by direct focused ion beam patterning of bulk single crystal material. The domain structures which appear in these single crystal dots, after cooling through the Curie temperature, were observed to form into quadrants, with each quadrant consisting of fine 90 degrees stripe domains. The reason that these rather complex domain configurations form is uncertain, but we consider and discuss three possibilities for their genesis: first, that the quadrant features initially form to facilitate field-closure, but then develop 90 degrees shape compensating stripe domains in order to accommodate disclination stresses; second, that they are the result of the impingement of domain packets which nucleate at the sidewalls of the dots forming "Forsbergh" patterns (essentially the result of phase transition kinetics); and third, that 90 degrees domains form to conserve the shape of the nanodot as it is cooled through the Curie temperature but arrange into quadrant packets in order to minimize the energy associated with uncompensated surface charges (thus representing an equilibrium state). While the third model is the preferred one, we note that the second and third models are not mutually exclusive.},
author = {Schilling, A. and Byrne, D. and Catalan, Gustau and Webber, Kyle Grant and Genenko, Y. A. and Wu, G. S. and Scott, J. F. and Gregg, J. M.},
doi = {10.1021/nl901661a},
faupublication = {no},
journal = {Nano Letters},
pages = {3359-3364},
peerreviewed = {Yes},
title = {{Domains} in {Ferroelectric} {Nanodots}},
volume = {9},
year = {2009}
}
@article{faucris.111509244,
abstract = {The mechanical stress-induced domain switching and energy dissipation in morphotropic phase boundary (1 - x)(Bi(1-y)La(y))FeO(3)-xPbTiO(3) during uniaxial compressive loading have been investigated at three different temperatures. The strain obtained was found to decrease with increasing lanthanum content, although a sharp increase in strain was observed for compositions doped with 7.5 and 10 at. % La. Increased domain switching was found in compositions with decreased tetragonality. This is discussed in terms of the competing influences of the amount of domain switching and the spontaneous strain on the macroscopic behavior under external fields. Comparison of the mechanically and electrically dissipated energy showed significant differences, discussed in terms of the different microscopic interactions of electric field and stress. (C) 2011 American Institute of Physics. [doi:10.1063/1.3555599]},
author = {Leist, T. and Webber, Kyle Grant and Jo, Wook and Granzow, T. and Aulbach, E. and Suffner, J. and Roedel, J.},
doi = {10.1063/1.3555599},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Domain} switching energies: {Mechanical} versus electrical loading in {La}-doped bismuth ferrite-lead titanate},
volume = {109},
year = {2011}
}
@inproceedings{faucris.272200353,
address = {CHESTER},
author = {Gadelmawla, Ahmed and Rieß, Kevin and Hinterstein, M. and Webber, Kyle Grant and Khansur, Neamul Hayet},
booktitle = {ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES},
faupublication = {yes},
keywords = {ferroelectrics; Na0.5Bi0.5TiO3; in situ HTK-XRD; perovskites},
note = {CRIS-Team WoS Importer:2022-04-01},
pages = {C752-C752},
peerreviewed = {unknown},
publisher = {INT UNION CRYSTALLOGRAPHY},
title = {{Effect} of {Bi} non-stoichiometry on the crystallographic structure of {Na1}/{2Bi1}/{2TiO3}},
year = {2021}
}
@article{faucris.237941207,
abstract = {Electrochromic devices operating in the near infrared are being developed as a part of smart windows that can dynamically modulate visible light and heat transmittance of solar irradiation, dependent on weather conditions and personal preferences. Here, doped metal oxide nanocrystals are used to obtain the desired effect in the infrared spectral region. Specifically, the infrared transmittance is electrochemically modulated by control of the carrier concentration in the nanocrystals. While indium tin oxide nanocrystals are already known to provide this effect, the consequence of ligand treatment during preparation of the nanocrystal electrode on the electrochromic properties is studied. The type of ligand treatment is shown to affect the surface morphology, as well as the localized plasmon resonance energy of the nanocrystal films. A short and convenient treatment by ethanedithiol cross-linking ligands is shown to provide superior results as compared with the formic acid treatment used in the previous work. Future work combining windows based on optimized electrochromic effects in the near infrared combined with those in the visible spectral range will simultaneously improve building energy efficiency and indoor human comfort.},
author = {Mashkov, Oleksandr and Körfer, Julien and Eigen, Andreas and Yousefi Amin, Amir-Abbas and Killilea, Niall Andrew and Barabash, Anastasiia and Sytnyk, Mykhailo and Khansur, Neamul Hayet and Halik, Marcus and Webber, Kyle Grant and Heiß, Wolfgang},
doi = {10.1002/adem.202000112},
faupublication = {yes},
journal = {Advanced Engineering Materials},
keywords = {electrochromic windows; ligand exchange; localized surface plasmon resonances; metal oxide nanocrystals},
note = {CRIS-Team Scopus Importer:2020-05-02},
peerreviewed = {Yes},
title = {{Effect} of {Ligand} {Treatment} on the {Tuning} of {Infrared} {Plasmonic} {Indium} {Tin} {Oxide} {Nanocrystal} {Electrochromic} {Devices}},
year = {2020}
}
@article{faucris.318366098,
abstract = {The temperature-dependent Rayleigh behavior of polycrystalline lead-free Lix(Na0.5K0.5)1-xNbO3 ceramics was characterized to measure the reversible and irreversible piezoelectric response of different compositions with varying Li content. The results revealed that all compositions showed peak values of both reversible and irreversible piezoelectric response near the polymorphic phase boundary. Additionally, depending on the crystal structure, Li content affected the irreversible and reversible contributions. Specifically, at room temperature, there was a notable increase in the irreversible contribution with rising Li content, whereas, within the tetragonal region, the change in Li content predominantly influenced the reversible contributions, resulting in their reduction. These results are discussed in conjunction with temperature-dependent X-ray diffraction and transmission electron microscopy data, which indicated that the lattice distortion and domain structure play an important role in the temperature-dependent variation in the piezoelectric response.},
author = {Martin, Alexander and Khansur, Neamul Hayet and Urushihara, Daisuke and Asaka, Toru and Kakimoto, Ken ichi and Webber, Kyle Grant},
doi = {10.1016/j.actamat.2024.119691},
faupublication = {yes},
journal = {Acta Materialia},
keywords = {Lead-free piezoceramics; Polymorphic phase boundary; Rayleigh behavior},
note = {CRIS-Team Scopus Importer:2024-02-16},
peerreviewed = {Yes},
title = {{Effect} of {Li} on the intrinsic and extrinsic contributions of the piezoelectric response in {Lix}({Na0}.{5K0}.5)1-{xNbO3} piezoelectric ceramics across the polymorphic phase boundary},
volume = {266},
year = {2024}
}
@article{faucris.266343278,
abstract = {Na1/2Bi1/2TiO3 (NBT) with varying Bi content has gained significant interest as a potential new material for solid-oxide fuel cells and oxygen separation membranes because of its excellent oxygen-ion conductivity. In this work, the effect of varying Bi content in NBT ceramics of compositions Na1/2BixTiO2.25+1.5x, where x = 0.485-0.510, on the temperature-dependent mechanical and dielectric properties and the crystal structure has been investigated, as these applications expose the components to high thermal and mechanical fields. The effects of Bi variation on phase compositions and structural transitions were systematically investigated by scanning electron microscopy-energy dispersive x-ray analyses and neutron diffraction at room temperature, in situ high-temperature x-ray diffraction, dielectric permittivity, and mechanical measurements. In-depth analysis of the temperature-dependent data shows that the Bi content of the samples does not alter the average crystal structure of the NBT; however, the temperature-dependent behavior of the latter depend on variations in Bi content and the associated oxygen vacancy concentration. This change in phase transition temperature displays a good correlation with the temperature-dependent ferroelastic response and with the Bi content. },
author = {Gadelmawla, Ahmed and Rieß, Kevin and Birkenstock, Johannes and Hinterstein, Manuel and Webber, Kyle Grant and Khansur, Neamul Hayet},
doi = {10.1063/5.0070594},
faupublication = {yes},
journal = {Journal of Applied Physics},
note = {CRIS-Team Scopus Importer:2021-11-19},
peerreviewed = {Yes},
title = {{Effect} of varying {Bi} content on the temperature-dependent mechanical, dielectric, and structural properties of nominal {Na1}/{2Bi1}/{2TiO3}},
volume = {130},
year = {2021}
}
@article{faucris.111499784,
abstract = {The dynamic properties of elastic domain walls in BaTiO3 were investigated using resonance ultrasonic spectroscopy (RUS). The sequence of phase transitions is characterized by minima in the temperature dependence of RUS resonance frequencies and changes in Q factors (resonance damping). Damping is related to the friction of mobile twin boundaries (90 degrees ferroelectric walls) and distorted polar nanoregions (PNRs) in the cubic phase. Damping is largest in the tetragonal phase of ceramic materials but very low in single crystals. Damping is also small in the low-temperature phases of the ceramic sample and slightly increases with decreasing temperature in the single crystal. The phase angle between the real and imaginary part of the dynamic response function changes drastically in the cubic and tetragonal phases and remains constant in the orthorhombic phase. Other phases show a moderate dependence of the phase angle on temperature showing systematic changes of twin microstructures. Mobile twin boundaries (or sections of twin boundaries such as kinks inside twin walls) contribute strongly to the energy dissipation of the forced oscillation while the reduction in effective modulus due to relaxing twin domains is weak. Single crystals and ceramics show strong precursor softening in the cubic phase related to polar nanoregions (PNRs). The effective modulus decreases when the transition point of the cubic-tetragonal transformation is approached from above. The precursor softening follows temperature dependence very similar to recent results from Brillouin scattering. Between the Burns temperature (approximate to 586 K) and T-c at 405 K, we found a good fit of the squared RUS frequency [similar to Delta (C-11 - C-12)] to a Vogel-Fulcher process with an activation energy of similar to 0.2 eV. Finally, some first-principles-based effective Hamiltonian computations were carried out in BaTiO3 single domains to explain some of these observations in terms of the dynamics of the soft mode and central mode. DOI: 10.1103/PhysRevB.87.014106},
author = {Salje, Ekhard K. H. and Carpenter, Michael A. and Nataf, Guillaume F. and Picht, Gunnar and Webber, Kyle Grant and Weerasinghe, Jeevaka and Lisenkov, S. and Bellaiche, L.},
doi = {10.1103/PhysRevB.87.014106},
faupublication = {no},
journal = {Physical Review B},
month = {Jan},
peerreviewed = {Yes},
title = {{Elastic} excitations in {BaTiO3} single crystals and ceramics: {Mobile} domain boundaries and polar nanoregions observed by resonant ultrasonic spectroscopy},
volume = {87},
year = {2013}
}
@article{faucris.114435684,
abstract = {The high crystallographic strain and polarization of BiFeO3 are attractive, but utilization of bulk BiFeO3 has been hindered by large leakage current and high coercive field. Here, we report on the electrical conductivity and ferroelasticity of BiFeO3 substituted with 10 and 20 mol% Bi0.5K0.5TiO3. The electrical conductivity is reduced by several orders of magnitude with donor substitution of Fe with Ti, which also suppressed the strong dependence of the conductivity on partial pressure of oxygen. Hard ferroelastic properties of the as-sintered materials were demonstrated by stress-strain measurements. The coercive stress was strongly reduced by quenching from above the ferroelectric to paraelectric phase transition, and the remanent strain increased and coercive stress decreased with increasing temperature up to 400 degrees C. Ferroelastic hardening was also observed with increasing Ti-donor substitution. The effect of donor substitution is discussed with respect to point defect chemistry and possible hardening mechanisms related to point defects. (C) 2015 Elsevier Ltd. All rights reserved.},
author = {Wefring, Espen Tjonneland and Schader, Florian H. and Webber, Kyle Grant and Einarsrud, Mad-Ann and Grande, Tor},
doi = {10.1016/j.jeurceramsoc.2015.09.044},
faupublication = {no},
journal = {Journal of the European Ceramic Society},
keywords = {BiFeO3;Donor substitution;Conductivity;Ferroelasticity},
pages = {497-506},
peerreviewed = {Yes},
title = {{Electrical} conductivity and ferroelastic properties of {Ti}-substituted solid solutions (1-x) {BiFeO3} - x {Bi0}.{5K0}.{5TiO3}},
volume = {36},
year = {2016}
}
@article{faucris.204032152,
abstract = {In this study, the macroscopic mechanical behavior was characterized for poled and unpoled polycrystalline (1-x)(Na1/2Bi1/2)TiO3-xBaTiO(3) (NBT-xBT) for compositions across the morphotropic phase boundary (MPB). Due to a field-induced ferroelectric phase transformation, NBT-xBT compositions near the MPB (x = 6-7 mol%) showed a significant decrease in the coercive stress for electrically poled samples. The apparent difference in mechanical behavior is suggested to be due to an irreversible electric-field-induced transformation to long-range ferroelectric order in the poled samples. The results indicate a significant difference in the critical stresses for the relaxor-ferroelectric transition and ferroelastic domain wall motion, which can have important effects on applications for lead-free ferroelectrics. To further illustrate this, a method was developed to electrically depole NBT-xBT at room temperature, resulting in an unpoled NBT-xBT material with long-range ferroelectric order. Mechanical testing revealed analogous macroscopic ferroelastic behavior to the poled samples, despite the lack of a piezoelectric response.},
author = {Martin, Alexander and Khansur, Neamul Hayet and Webber, Kyle Grant},
doi = {10.1016/j.jeurceramsoc.2018.06.017},
faupublication = {yes},
journal = {Journal of the European Ceramic Society},
keywords = {Electrical depoling;Ferroelastie properties;Dielectric properties;Lead-free},
pages = {4623-4630},
peerreviewed = {Yes},
title = {{Electric} field-induced changes in the ferroelastic behavior of ({Na1}/{2Bi1}/2){TiO3}-{BaTiO3}},
volume = {38},
year = {2018}
}
@article{faucris.209902357,
author = {Martin, Alexander and Khansur, Neamul Hayet and Webber, Kyle Grant},
doi = {10.1016/j.jeurceramsoc.2018.06.017},
faupublication = {yes},
journal = {Journal of the European Ceramic Society},
keywords = {Lead-free; Dielectric properties; Ferroelastic properties; Electrical depoling},
pages = {4623-4630},
peerreviewed = {Yes},
title = {{Electric} field-induced changes in the ferroelastic behavior of ({Na1}/{2Bi1}/2){TiO3}-{BaTiO3}},
volume = {38},
year = {2018}
}
@article{faucris.123367024,
abstract = {Bismuth ferrite, BiFeO3, is an important multiferroic material that has attracted remarkable attention for potential applications in functional devices. While thin films of BiFeO3 are attractive for applications in nanoelectronics, bulk polycrystalline BiFeO3 has great potential as a lead-free and/or high-temperature actuator material. However, the actuation mechanisms in bulk BiFeO3 are still to be resolved. Here we report the microscopic origin of electric-field-induced strain in bulk BiFeO3 ceramic by means of in situ high-energy X-ray diffraction. Quantification of intrinsic lattice strain and extrinsic domain switching strain from diffraction data showed that the strain response in rhombohedral bulk BiFeO3 is primarily due to non-180 degrees ferroelectric domain switching, with no observable change in the phase symmetry, up to the maximum field used in the study. The origin of strain thus differs from the strain mechanism previously shown in thin film BiFeO3, which gives a similar strain/field ratio as rhombohedral bulk BiFeO3. A strong post-poling relaxation of switched non-180 degrees ferroelectric domains has been observed and hypothesized to be due to intergranular residual stresses with a possible contribution from the conductive nature of the domain walls in BiFeO3 ceramics.},
author = {Khansur, Neamul H. and Rojac, Tadej and Damjanovic, Dragan and Reinhard, Christina and Webber, Kyle Grant and Kimpton, Justin A. and Daniels, John E. and Khansur, Neamul Hayet},
doi = {10.1111/jace.13839},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
pages = {3884-3890},
peerreviewed = {Yes},
title = {{Electric}-{Field}-{Induced} {Domain} {Switching} and {Domain} {Texture} {Relaxations} in {Bulk} {Bismuth} {Ferrite}},
volume = {98},
year = {2015}
}
@article{faucris.119737464,
abstract = {An electric-field-induced paraelectric cubic to ferroelectric tetragonal phase transformation has been directly observed in prototypical polycrystalline BaTiO3 at temperatures above the Curie point (T-C) using in situ high-energy synchrotron X-ray diffraction. The transformation persisted to a maximum temperature of 4 degrees C above T-C. The nature of the observed field-induced transformation and the resulting development of domain texture within the induced phase were dependent on the proximity to the transition temperature, corresponding well to previous macroscopic measurements. The transition electric field increased with increasing temperature above T-C, while the magnitude of the resultant tetragonal domain texture at the maximum electric field (4 kV mm(-1)) decreased at higher temperatures. These results provide insights into the phase transformation behavior of a prototypical ferroelectric and have important implications for the development of future large-strain phase-change actuator materials. (C) 2014 AIP Publishing LLC.},
author = {Wang, Zhiyang and Webber, Kyle Grant and Hudspeth, Jessica M. and Hinterstein, Manuel and Daniels, John E.},
doi = {10.1063/1.4898573},
faupublication = {no},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Electric}-field-induced paraelectric to ferroelectric phase transformation in prototypical polycrystalline {BaTiO3}},
volume = {105},
year = {2014}
}
@article{faucris.111476464,
abstract = {The strain- and polarization-electric field behavior was characterized at room temperature for Pb0.98Ba0.01(Zr1-xTix)(0.98)Nb0.02O3, 0.40 <= x <= 0.60. The investigated compositions were located in the vicinity of the morphotropic phase boundary, giving insight into the influence of crystal structure on the hysteretic ferroelectric behavior. The remanent strain of particular compositions is shown to be larger than theoretically allowed by ferroelectric switching alone, indicating the presence of additional remanent strain mechanisms. A phenomenological free energy analysis was used to simulate the effect of an applied electric field on the initial equilibrium phase. It is shown that electric-field-induced phase transitions in polycrystalline ferroelectrics can account for the experimental observations. The experimental and simulation results are contrasted to neutron diffraction measurements performed on representative compositions in the virgin and remanent states.},
author = {Franzbach, Daniel J. and Seo, Yo-Han and Studer, Andrew J. and Zhang, Yichi and Glaum, Julia and Daniels, John E. and Koruza, Jurij and Bencan, Andreja and Malic, Barbara and Webber, Kyle Grant},
doi = {10.1088/1468-6996/15/1/015010},
faupublication = {no},
journal = {Science and Technology of Advanced Materials},
keywords = {ferroelectricity;PZT;field induced phase transitions;morphotropic phase boundary},
peerreviewed = {Yes},
title = {{Electric}-field-induced phase transitions in co-doped {Pb}({Zr1}-{xTix}){O}-3 at the morphotropic phase boundary},
volume = {15},
year = {2014}
}
@article{faucris.122253604,
abstract = {The strain and polarization hystereses of lead-free 0.94Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3) during unipolar electric field loading are obtained from room temperature to 150 degrees C under uniaxial compressive stress up to 446 MPa. At intermediate temperatures a stress-dependent peak evolves in both the maximum strain and polarization. At 125 degrees C a large strain with a large-signal piezoelectric coefficient d(33)* of 884 pm V-1 is observed, which decays upon the application of stress. This behavior is rationalized with a change in the primary strain mechanism from domain switching at low temperatures to a reversible electric field-induced transition from an ergodic relaxor state to a long-range order at high temperatures. Moreover, the energy terms w (the output mechanical work) and e(P) (the charged electrical energy density) that are related to the deformation and the polarization, respectively, are analyzed and used to define a large-signal efficiency eta* = w(w + e(P))(-1). It is found that eta* saturates at similar to 150 MPa but decreases with increasing temperature and electric field. It is furthermore observed that notable strains are achieved at stress levels even far beyond the quasi-statically determined blocking force. Therefore, it is proposed that the presented testing procedure is suited to assess the dynamic actuatoric performance of a piezoceramic. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Dittmer, Robert and Webber, Kyle Grant and Aulbach, Emil and Jo, Wook and Tan, Xiaoli and Rödel, Jürgen},
doi = {10.1016/j.actamat.2012.11.012},
faupublication = {no},
journal = {Acta Materialia},
keywords = {Lead-free piezoceramics;Uniaxial stress;Electromechanical properties;Actuators;Relaxors},
pages = {1350-1358},
peerreviewed = {Yes},
title = {{Electric}-field-induced polarization and strain in 0.94({Bi1}/{2Na1}/2){TiO3}-0.{06BaTiO}(3) under uniaxial stress},
volume = {61},
year = {2013}
}
@article{faucris.247781779,
abstract = {Lead-free (Li,Na,K)NbO3-based multilayered piezoceramics were prepared, and their large-signal piezoelectric properties, under combined electrical and mechanical loadings, were characterized from 25 degrees C to 100 degrees C. Under zero stress, the multilayer exhibited a high large-signal piezoelectric constant},
author = {Nishiyama, Hiroshi and Martin, Alexander and Hatano, Keiichi and Kishimoto, Sumiaki and Sasaki, Nobuhiro and Khansur, Neamul Hayet and Webber, Kyle Grant and Kakimoto, Ken-Ichi},
doi = {10.1063/5.0029615},
faupublication = {yes},
journal = {Journal of Applied Physics},
note = {CRIS-Team WoS Importer:2021-01-15},
peerreviewed = {Yes},
title = {{Electric}-field-induced strain of ({Li},{Na},{K}){NbO3}-based multilayered piezoceramics under electromechanical loading},
volume = {128},
year = {2020}
}
@article{faucris.111500884,
abstract = {Electric field-induced phase transitions in [110](c)-oriented BaTiO3 single crystals were studied by macroscopic electrical measurements in the temperature range from 20 degrees C to 50 degrees C. Discontinuous, hysteretic jumps in the polarization and strain were observed, indicating a tetragonal <-> orthorhombic phase transition. The critical electric field to induce the transition was found to shift to higher values with increasing temperature. The Landau-Devonshire theory was used to analyze the observed electric field-induced T <-> O phase transitions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4769368]},
author = {Franzbach, D. J. and Gu, Y. J. and Chen, L. Q. and Webber, Kyle Grant},
doi = {10.1063/1.4769368},
faupublication = {no},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Electric} field-induced tetragonal to orthorhombic phase transitions in [110](c)-oriented {BaTiO3} single crystals},
volume = {101},
year = {2012}
}
@article{faucris.114449104,
abstract = {
An electric field–temperature (E-T) phase diagram for a lead-free 0.5 mol. % Mn-doped Bi(Na0.1K0.9)TiO3 ceramics was investigated. The x-ray diffraction, dielectric and polarization measurements revealed relaxor behavior and were used to characterize the stability regions of the non-ergodic relaxor, ergodic relaxor and electric field induced ferroelectric states. As indicated by the polarization–current density profiles, transformation between two electric fields, induced ferro- electric states with opposite polarization direction arise via a two-step process through an interme- diate relaxor state. Interplay between the ferroelectric state conversion and intermediate relaxor state is governed by the dynamics of polarization relaxation. The presented E-T phase diagram revealed the effects of the applied electric field and temperature on stability regions. This is of spe- cial interest since the Bi0.5(Na0.1K0.9)0.5TiO3 ceramics were proposed as a potential piezoceramic material.
},
author = {Ehara, Yoshitaka and Novak, Nikola and Yasui, Shintaro and Itoh, Mitsuru and Webber, Kyle Grant},
doi = {10.1063/1.4938759},
faupublication = {yes},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Electric}-field-temperature phase diagram of {Mn}-doped {Bi}-0.5({Na0}.{9K0}.1)(0.5){TiO3} ceramics},
volume = {107},
year = {2015}
}
@article{faucris.123575584,
author = {Wang, Ke and Yao, Fang-Zhou and Koruza, Jurij and Cheng, Li-Qian and Schader, Florian H. and Zhang, Mao-Hua and Roedel, Juergen and Li, Jing-Feng and Webber, Kyle Grant},
doi = {10.1111/jace.14661},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
keywords = {electromechanical properties; lead-free ceramics; niobium/niobium compounds; piezoelectric materials/properties; stress},
pages = {2116-2122},
peerreviewed = {Yes},
title = {{Electromechanical} properties of {CaZrO3} modified ({K},{Na}){NbO3}-based lead-free piezoceramics under uniaxial stress conditions},
volume = {100},
year = {2017}
}
@article{faucris.279549654,
abstract = {The small-signal dielectric and piezoelectric coefficients of paper-derived sodium potassium niobate, K0.5Na0.5NbO3 (KNN), were compared with those of conventionally prepared samples. Results show similar functional properties of paper-derived KNN without significantly decreasing the small-signal piezoelectric coefficient. The structure and microstructure analysis of conventional KNN and paper-derived KNN did not reveal any significant difference in the crystal structure and grain size. However, the temperature-dependent inter-ferroelectric phase transition temperature estimated from the temperature-dependent dielectric permittivity data revealed a decrease of approximately 18°C for the paper-derived KNN and is possibly associated with the structural and microstructural defects. This work indicates that optimizing suspension chemistry and sintering conditions will be critical to enhance the functional response of paper-derived KNN further. Moreover, paper-derived ceramic processing, a novel and cost-effective additive manufacturing technology, can be potentially used to fabricate other electroceramics with a wide range of porosities and sizes as well as complex geometries and multilayer structures.},
author = {Wahl, Larissa and Maier, Juliana and Schmiedeke, Samuel and The-An Pham, and Fey, Tobias and Webber, Kyle Grant and Travitzky, Nahum and Khansur, Neamul Hayet},
doi = {10.1111/jace.18655},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
keywords = {KNN; lead-free ferroelectrics; paper-derived ceramics; piezoelectrics},
note = {CRIS-Team Scopus Importer:2022-08-05},
peerreviewed = {Yes},
title = {{Electromechanical} properties of paper-derived potassium sodium niobate piezoelectric ceramics},
year = {2022}
}
@article{faucris.240051814,
abstract = {This work presents the fabrication of dense polycrystalline barium titanate (BaTiO3, BT) for electromechanical transduction using robocasting and cold isostatic pressing (CIP). The use of CIP as post-treatment is proposed to eliminate defects and increase the density of robocasted parts to improve the piezoelectric performance. For robocasting, pastes containing 50 and 52 vol% are developed; the resulting green robocasted parts are CIPed at 100 and 150 MPa. Using this proposed technique, samples robocasted with BT52 and CIPed at 150 MPa display a relative density of approximate to 98%, comparable with reference polycrystalline samples. In addition, an increase in both the piezoelectric charge and voltage coefficient is observed in robocasted parts, with the values up to 195 pC/N and 12 x 10(-3) Vm N-1, respectively. These values, which are comparable with previous studies of polycrystalline BT, indicate that the combined robocasting and CIP technique is a possible method for producing 3D printed piezoelectric sensors.},
author = {Lorenz, Mylena Mayara and Martin, Alexander and Webber, Kyle Grant and Travitzky, Nahum},
doi = {10.1002/adem.202000325},
faupublication = {yes},
journal = {Advanced Engineering Materials},
note = {CRIS-Team WoS Importer:2020-07-03},
peerreviewed = {Yes},
title = {{Electromechanical} {Properties} of {Robocasted} {Barium} {Titanate} {Ceramics}},
year = {2020}
}
@article{faucris.266114326,
abstract = {The integration of functional ceramics with metals remains challenging due to the thermally activated processes and the incompatibilities that arise during the high-temperature ceramic sintering process. In order to overcome this, low-temperature processing methods can be employed. In this work, dense 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 thick films were deposited on low-cost, stainless-steel substrates at room temperature using an aerosol-deposition method. The key material parameters for a successful aerosol deposition of the powder were identified and used in the process, which resulted in homogeneous 15-µm-thick films. The as-deposited films can withstand electric fields of 900 kV⋅cm−1 and exhibit promising room-temperature energy-storage properties: the recoverable energy density reaches 7.0 J⋅cm−3 with an energy-storage efficiency of ∼70%. A post-deposition stress relaxation by annealing at 500°C further improves the recoverable energy density, leading to 9.8 J⋅cm−3 at 900 kV⋅cm−1 with an energy-storage efficiency of ∼80%. The energy-storage performance exhibits excellent temperature stability up to 200°C and an electric-field cycling stability up to 16 million cycles. The low-temperature integration of energy-storage-efficient thick films onto stainless steel opens up possibilities for numerous new, pulsed-power and power-conditioning electronic applications.},
author = {Sadl, Matej and Condurache, Oana and Bencan, Andreja and Dragomir, Mirela and Prah, Uros and Malic, Barbara and Deluca, Marco and Eckstein, Udo and Hausmann, Daniel and Khansur, Neamul Hayet and Webber, Kyle Grant and Ursic, Hana},
doi = {10.1016/j.actamat.2021.117403},
faupublication = {yes},
journal = {Acta Materialia},
keywords = {Aerosol deposition; Energy storage; Low-temperature processing; PMN–PT; Relaxor-ferroelectric; Stainless steel; Thick film},
note = {CRIS-Team Scopus Importer:2021-11-12},
peerreviewed = {Yes},
title = {{Energy}-storage-efficient 0.{9Pb}({Mg1}/{3Nb2}/3){O3}–0.{1PbTiO3} thick films integrated directly onto stainless steel},
volume = {221},
year = {2021}
}
@inproceedings{faucris.120014444,
author = {Wakily, Hakimeh and Koruza, Jurij and Ayrikyan, Azatuhi and Webber, Kyle Grant},
booktitle = {2016 Joint IEEE International Symposium on the Applications of Ferroelectrics, European Conference on Application of Polar Dielectrics, and Piezoelectric Force Microscopy Workshop, ISAF/ECAPD/PFM 2016},
doi = {10.1109/ISAF.2016.7578072},
faupublication = {yes},
isbn = {9781509018710},
keywords = {composite; electromechanic; ferroelectric; relaxor},
peerreviewed = {unknown},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
title = {{Enhanced} {Electromechanical} properties of ferroelectric {Bi1}/{2Na1}/{2TiO3} -{7BaTiO3}/{relaxorBi1}/{2Na1}/{2TiO3} -{25SrTiO3composites}},
year = {2016}
}
@article{faucris.258800067,
abstract = {Na1/2Bi1/2TiO3-based relaxor ferroelectrics are extensively investigated for use in transduction applications because of their relatively large electromechanical properties. Integration of these materials into devices, however, requires better temperature stability in addition to electromechanical properties. This work demonstrates a novel approach to enhance the temperature stability of the long-range ferroelectric order as well as to enhance electromechanical properties in a non-ergodic relaxor 0.93(Na1/2Bi1/2)TiO3-0.07BaTiO3 (NBT-7BT) without changing the chemical composition through, for example, chemical substitutions or second phase particles. The approach involves the room temperature deposition of copper electrodes directly on the relaxor ceramic substrate using the aerosol deposition (AD) method. The collision of solid-state particles with the substrate surface during AD results in large impact and residual stresses, inherent to the AD process, which are shown with piezo-response force microscopy to induce long-range ferroelectric domain ordering in non-ergodic relaxor NBT-7BT. Using Raman spectroscopy, the magnitude and depth profile of the stress-induced transformation are determined. It is demonstrated that deposition-induced stresses significantly increase the temperature stability of the electromechanical properties, where long-range ferroelectric ordering is observed up to 150 °C, which is approximately 41 °C higher than NBT-7BT samples without the AD processed electrode. Moreover, the AD treatment also facilitates ferroelectric domain switching at a lower electric field, enabling maximum polarization at a relatively lower field and an enhancement in the piezoelectric response. It is shown that the deposition-induced stress is responsible for such an enhancement. Importantly, this impact-stress-driven tailoring of electromechanical properties can potentially be utilized for other functional ceramic materials as well, where internal residual stress can result in enhanced functional properties.},
author = {Khansur, Neamul Hayet and Eckstein, Udo and Ursic, Hana and Sadl, Matej and Brehl, Martin and Martin, Alexander and Rieß, Kevin and de Ligny, Dominique and Webber, Kyle Grant},
doi = {10.1002/admi.202100309},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
keywords = {aerosol deposition; deposition-induced stress; electromechanical applications; lead-free relaxors; temperature stability},
note = {CRIS-Team Scopus Importer:2021-05-21},
peerreviewed = {Yes},
title = {{Enhanced} {Electromechanical} {Response} and {Thermal} {Stability} of 0.93({Na1}/{2Bi1}/2){TiO3}-0.{07BaTiO3} {Through} {Aerosol} {Deposition} of {Base} {Metal} {Electrodes}},
year = {2021}
}
@article{faucris.124206764,
abstract = {The macroscopic electromechanical behavior of lead-free bilayer composites was characterized at room temperature. One layer consisted of a nonergodic relaxor, (Bi1/2Na1/2)TiO3-7BaTiO(3), with an electric-field-induced long-range ferroelectric order, whereas the other is understood to be an ergodic relaxor [(Bi1/2Na1/2)TiO3-25SrTiO(3)] that undergoes a reversible electric-field-induced macroscopic nonpolar-to-polar transition. Microstructural evidence of a bilayer with low diffusion between the two components is also demonstrated. By taking advantage of the different macroscopic strain-and polarization-electric-field responses of the two constituents, internal mechanical and electrical fields can be developed that enhance the unipolar strain over that expected by a rule of mixtures approximation, thereby improving the properties needed for application of such materials to actuator systems. It is possible through further tailoring of the volume fractions and macroscopic properties of the constituents to optimize the electromechanical properties of multilayer lead-free ferroelectrics.},
author = {Ayrikyan, Azatuhi and Rojas, Virginia and Molina-Luna, Leopoldo and Acosta, Matias and Koruza, Jurij and Webber, Kyle Grant},
doi = {10.1109/TUFFC.2014.006673},
faupublication = {no},
journal = {IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control},
pages = {997-1006},
peerreviewed = {Yes},
title = {{Enhancing} {Electromechanical} {Properties} of {Lead}-{Free} {Ferroelectrics} {With} {Bilayer} {Ceramic}/{Ceramic} {Composites}},
volume = {62},
year = {2015}
}
@article{faucris.111565784,
abstract = {The influence of the uniaxial preload on the off-resonance actuation performance of piezoelectric ceramics was investigated for compressive preload values up to -80 MPa. The study was performed on soft-type lead zirconate titanate (PZT), being the most widely used piezoelectric material. The samples were analysed using the proportional loading method, which enables the simultaneous application of electrical and mechanical loads, thereby mimicking the real operation conditions over the full stress-strain range. An increase of the blocking stress and the longitudinal piezoelectric stress coefficient was observed for all the applied preload values. The optimum properties, a blocking stress of -56 MPa and a free strain of 0.23%, were obtained at a preload value of -40 MPa and electric field of 2 kV mm(-1). This represents an increase of 16% and 20%, respectively, as compared to the values obtained at the smallest preload. In addition, the maximum work output was increased by about 28%. Finally, the results obtained at the lowest preload of -4 MPa using the proportional loading method were compared to the operational ranges determined by other methods. The comparison revealed large discrepancies between the methods, originating from the different order of the application of electrical and mechanical fields and the inherent nonlinearity of ferroelectric materials. This discrepancy results in decreased actuator performance due to impedance mismatching, demonstrating the need for accurate determination of the actuator's operational range.},
author = {Koruza, Jurij and Franzbach, Daniel J. and Schader, Florian H. and Rojas, Virginia and Webber, Kyle Grant},
doi = {10.1088/0022-3727/48/21/215302},
faupublication = {no},
journal = {Journal of Physics D-Applied Physics},
keywords = {piezoelectric;actuator;blocking force;operational range;PZT},
peerreviewed = {Yes},
title = {{Enhancing} the operational range of piezoelectric actuators by uniaxial compressive preloading},
volume = {48},
year = {2015}
}
@article{faucris.111477784,
abstract = {Hetero-agglomeration of precursor particles was employed to achieve a homogeneous distribution of tetragonal zirconia (TZ) grains within a lead zirconate titanate (PZT) ceramic matrix. The surface charge of the zirconia particles in the aqueous suspension was modified by the addition of citric acid. At pH 5, the citric-acid-modified TZ particles were negatively charged, while the PZT particles were positively charged, which led to the agglomeration of the two types of particles. The homogeneity of the TZ distribution in the PZT TZ ceramic composites prepared from the hetero-agglomerated particles was evaluated using Voronoi-diagram analyses. The results showed that the homogeneity of the composites prepared using the citric-acid-modified TZ particles was higher than in the case where the TZ particles were not modified. The curves for the crack-growth resistance were also determined in order to investigate the impact of particle homogeneity on the fracture behavior. (C) 2013 Elsevier Ltd. All rights reserved.},
author = {Trefalt, Gregor and Bencan, Andreja and Kamplet, Mitja and Malic, Barbara and Seo, Yohan and Webber, Kyle Grant},
doi = {10.1016/j.jeurceramsoc.2013.09.014},
faupublication = {no},
journal = {Journal of the European Ceramic Society},
keywords = {PZT;Colloidal suspension;Composites;Voronoi diagram;Mechanical properties},
pages = {669-675},
peerreviewed = {Yes},
title = {{Evaluation} of the homogeneity in {Pb}({Zr},{Ti}){O}-3-zirconia composites prepared by the hetero-agglomeration of precursors using the {Voronoi}-diagram approach},
volume = {34},
year = {2014}
}
@article{faucris.226675063,
abstract = {A novel technique for the rapid room-temperature deposition of porous ceramic, glass, or metal thick films using the aerosol deposition (AD) method is presented. The process is based on the co-deposition of the desired film material and a second water-soluble constituent, resulting in a ceramic-ceramic composite. Following the subsequent removal of water-soluble end member, a network of pores is retained. To demonstrate the process, porous BaTiO3 thick films were fabricated through co-deposition with NaCl. Microstructural images show the clear development of a porous structure, which was found to enhance the dielectric properties over dense thick films, possibly related to the lower extent of internal residual stress. This simple but highly effective porous structure fabrication can be applied to any film and substrate material stable in water and is promising for the application of AD-processed films in gas sensors, solid oxide fuel cells, and humidity sensors.},
author = {Khansur, Neamul Hayet and Eckstein, Udo and Sadl, Matej and Ursic, Hana and Webber, Kyle Grant},
doi = {10.1111/jace.16772},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
keywords = {ceramic matrix composites; dielectric materials/properties; porous materials; sensors},
note = {CRIS-Team Scopus Importer:2019-09-17},
peerreviewed = {Yes},
title = {{Fabrication} of porous thick films using room-temperature aerosol deposition},
year = {2019}
}
@article{faucris.319064594,
abstract = {Recent advances in machine learning capabilities have increased interest in materials research to improve the efficiency of materials discovery and optimization as well as to better understand the underlying phenomena responsible for the observed physical properties. While combinatorial chemistry and compositional engineering is well established in the development of pharmaceutical and chemical products, its use in the field of bulk functional polycrystalline ceramics is far from mature. In this work, a critical review of a high-throughput powder-based dispensing system is provided and the challenges involved with the transition from a conventional, human resources intensive workflow to a fully automated process are highlighted. Based on the lead-free piezoelectric BiFeO3–BaTiO3 binary system, the applicability and robustness of high-throughput engineering is investigated to increase data point density in phase diagrams, including the composition variations of the resulting materials. This work presents 16 different BiFeO3–BaTiO3 compositions at four different calcination temperatures, both demonstrating the potential of the system. This is coupled to automated crystal structure analysis, which will be used to investigate the role of calcination temperature on the resulting compositions at room temperature.},
author = {Eckstein, Udo and Kuhfuß, Michel and Fey, Tobias and Webber, Kyle Grant},
doi = {10.1002/adem.202302126},
faupublication = {yes},
journal = {Advanced Engineering Materials},
keywords = {combinatorial chemistry; compositional engineering; high-throughput XRD; powder dispensing; solid state reactions; structural characterizations},
note = {CRIS-Team Scopus Importer:2024-03-01},
peerreviewed = {Yes},
title = {{Feasibility} of {Powder}-{Based} {High}-{Throughput} {Synthesis} for {Ceramics} {Development}: {Case} {Study} on the {Influence} of {Calcination} {Temperature} in {BiFeO3}-{BaTiO3}},
year = {2024}
}
@article{faucris.119783664,
abstract = {In this study, the macroscopic mechanical behavior was characterized as a function of temperature (-150 degrees C to 400 degrees C) for polycrystalline (Na0.5K0.5)NbO3 with three dopant concentrations. Dopants can improve certain electromechanical properties and, in the case of NKN and Li+, shift the orthorhombic-to-tetragonal phase transition temperature to lower temperatures. In this study, the mechanical behavior of undoped NKN, LNKN6 with 6 mol. % Li+, and LNKN6 with additional dopants was characterized and compared with the temperature dependent dielectric response and crystal structure. During mechanical loading, the samples showed a nonlinear hysteretic response. At low temperatures, this is understood to be due to ferroelasticity. At temperatures in the vicinity of the orthorhombic-tetragonal phase transition temperature, a closed hysteresis behavior was observed, corresponding to a local maximum of the critical ferroelastic stress and a minimum in the remanent strain. The observed closed hysteresis behavior is suggested to be due to a stress-induced structural phase transformation. Published by AlP Publishing.},
author = {Martin, Alexander and Kakimoto, Ken-Ichi and Hatano, Keiichi and Doshida, Yutaka and Webber, Kyle Grant},
doi = {10.1063/1.4989759},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Ferroelastic} behavior across the orthorhombic-to-tetragonal phase transition region of {NKN}-based lead-free ferroelectrics},
volume = {122},
year = {2017}
}
@article{faucris.106261364,
abstract = {The ferroelectric, ferroelastic, piezoelectric, and dielectric properties of co-doped, soft-type Pb(Zr,Ti)O3 were measured from −150°C to 350 °C, highlighting the importance of temperature and defects on the electromechanical response. Small signal piezoelectric measurements revealed a linear increase with increasing temperatures below 0 °C, followed by a maximum at approximately 50 °C. The low temperature properties correspond well to observed changes in the large-field response during the application of an external electrical and mechanical field. The results illustrate the importance of understanding phase boundary effects in order to determine a useable temperature range and to tailor future lead free piezoelectric materials for cryogenic electromechanical applications.},
author = {Kaeswurm, Barbara and Schader, Florian and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2017.10.204},
faupublication = {yes},
journal = {Ceramics International},
keywords = {ferroelasticity; ferroelectricity; phase boundary; piezoelectricity},
pages = {2358-2363},
peerreviewed = {Yes},
title = {{Ferroelectric}, {Ferroelastic}, {Piezoelectric}, and {Dielectric} {Properties} of {Lead} {Zirconate} {Titanate} from –150°{C} to 350°{C}},
volume = {44},
year = {2018}
}
@article{faucris.209902701,
author = {Martin, Alexander and Khansur, Neamul Hayet and Rieß, Kevin and Webber, Kyle Grant},
doi = {10.1016/j.jeurceramsoc.2018.12.026},
faupublication = {yes},
journal = {Journal of the European Ceramic Society},
keywords = {Lead-free relaxor ferroelectrics; Time-dependent properties; Field-induced phase transformation; Ferroelasticity},
peerreviewed = {Yes},
title = {{Frequency} dependence of the relaxor-to-ferroelectric transition under applied electrical and mechanical fields},
year = {2018}
}
@article{faucris.247288686,
abstract = {The ferroelectric, ferroelastic, and dielectric properties as well as the crystal structure were investigated for polycrystalline donor doped lead zirconate titanate (PZT) with grain sizes ranging from 0.25 to 5 μm, which were prepared using a novel zirconium titanium hydrate precursor (ZTH) with a specific surface area of 310 m2/g. Piezoforce microscopy was used to investigate the change in the domain structure, revealing a change in the domain configuration from a complex 3D structure to a simple lamellar domain formation at a 1 μm grain size that corresponded to a rapidly increasing internal mechanical stress observed with in situ synchrotron x-ray experiments. The correlation between the change in domain configuration, increasing internal stresses, effects of poling on the crystal structure, and the macroscopic ferroelectric and ferroelastic properties are discussed in detail, allowing a deeper understanding of size effects in polycrystalline donor doped PZT ceramics. },
author = {Picht, Gunnar and Khansur, Neamul Hayet and Webber, Kyle Grant and Kungl, Hans and Hoffmann, Michael J. and Hinterstein, Manuel},
doi = {10.1063/5.0029659},
faupublication = {yes},
journal = {Journal of Applied Physics},
note = {CRIS-Team Scopus Importer:2020-12-25},
peerreviewed = {Yes},
title = {{Grain} size effects in donor doped lead zirconate titanate ceramics},
volume = {128},
year = {2020}
}
@article{faucris.111510124,
abstract = {Piezoelectric actuators outperform other technological solutions in the area of high-speed, high-force and high-accuracy displacement, but are only able to generate strains of about 0.2%. The load capability is generally quantified in terms of a blocking force, which is the force sustained under electric field at zero displacement. Stress-strain curves in a temperature regime from room temperature up to 150 degrees C on electrically loaded soft lead zirconate titanate (PZT) are generated to determine the blocking stress. The ensuing nonlinear behaviour is discussed in terms of ferroelectric and ferroelastic switching and contrasted to idealized linear constitutive behaviour as often assumed by manufacturers. The blocking stress is shown to increase with temperature due to an additional stiffening effect as a function of electric field. The actual mechanical work done is found to be larger than in the idealized case where linear constitutive behaviour is assumed.},
author = {Webber, Kyle Grant and Aulbach, Emil and Roedel, Juergen},
doi = {10.1088/0022-3727/43/36/365401},
faupublication = {no},
journal = {Journal of Physics D-Applied Physics},
peerreviewed = {Yes},
title = {{High} temperature blocking force measurements of soft lead zirconate titanate},
volume = {43},
year = {2010}
}
@article{faucris.236671162,
abstract = {The influence of uniaxial compressive stress on small-signal relative permittivity and direct piezoelectric coefficient of polycrystalline Li-modified (K0.5Na0.5)NbO3 (0, 2, and 4 mol. % Li) was characterized as a function of temperature from 25 to 450 °C. These data reveal corresponding anomalies in both the dielectric and piezoelectric properties near the well-known structural phase transitions in (KxNa1-x)NbO3. In particular, increasing stress was found to shift the orthorhombic-tetragonal (T O-T) and tetragonal-cubic (T C) phase boundaries to higher temperatures, thereby stabilizing the lower symmetry phases. Experimental results also show that stress up to a critical value flattens the piezoelectric response below T O-T, above which a monotonic decrease is observed. In contrast, permittivity is increased below T O-T with increasing stress. These results are used to construct a stress-temperature phase diagram of Li-modified (K0.5Na0.5)NbO3},
author = {Martin, Alexander and Khansur, Neamul Hayet and Eckstein, Udo and Rieß, Kevin and Kakimoto, Ken Ichi and Webber, Kyle Grant},
doi = {10.1063/1.5134554},
faupublication = {yes},
journal = {Journal of Applied Physics},
note = {CRIS-Team Scopus Importer:2020-03-31},
peerreviewed = {Yes},
title = {{High} temperature piezoelectric response of polycrystalline {Li}-doped ({K},{Na}){NbO3} ceramics under compressive stress},
volume = {127},
year = {2020}
}
@article{faucris.119783884,
abstract = {The dielectric constant and the direct piezoelectric coefficient as well as the macroscopic ferroelastic behavior of co-doped Pb(Zr,Ti)O-3 were characterized from 25 to 350 A degrees C as a function of uniaxial compressive stress. Experimental results show a decrease in the small signal piezoelectric coefficient and the permittivity with stress, although there exists a uniaxial compressive stress that significantly reduces the variation of the piezoelectric coefficient with increasing temperature, making it a possible method for sensors that operate over a large temperature range. In the vicinity of the depolarization temperature, the piezoelectric response rapidly decreases. This temperature, however, was observed well below the temperature at maximum permittivity. Experimental results reveal that uniaxial compressive stress shifts the temperature at maximum permittivity, giving insight into the effect of stress on the phase transition behavior in Pb(Zr,Ti)O-3, but does not apparently influence the depolarization temperature.},
author = {Schader, Florian and Isaia, Daniel and Weber, Michael and Aulbach, Emil and Webber, Kyle Grant},
doi = {10.1007/s10853-017-1817-8},
faupublication = {yes},
journal = {Journal of Materials Science},
pages = {3296-3308},
peerreviewed = {Yes},
title = {{High}-temperature stress-dependent piezoelectric and dielectric coefficient of soft {Pb}({Zr},{Ti}){O}-3},
volume = {53},
year = {2018}
}
@article{faucris.122255584,
abstract = {Polycrystalline 0.94(Bi(1/2)Na(1/2))TiO(3)-0.06BaTiO(3) samples were tested under uniaxial mechanical compression at various temperatures in the vicinity of the polar tetragonal to nonpolar tetragonal phase boundary. They are shown to display double loop-like stress-strain behavior, marked by a closed ferroelastic hysteresis loop. Thus, it forms a mechanical analog to the polarization-electric field hysteresis behavior of barium titanate above the Curie temperature. As temperature is increased there is an apparent loss of macroscopically observable ferroelasticity, despite the persistence of tetragonality. Macroscopic experimental results are discussed in conjunction with temperature-dependent and stress-dependent high-energy x-ray diffraction data. This reveals a phase transition below the Curie temperature, marked by a discontinuous change in lattice parameters and octahedral tilting during compressive mechanical loading. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3428373]},
author = {Webber, Kyle Grant and Zhang, Y. and Jo, Wook and Daniels, J. E. and Roedel, J.},
doi = {10.1063/1.3428373},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{High} temperature stress-induced "double loop-like" phase transitions in {Bi}-based perovskites},
volume = {108},
year = {2010}
}
@article{faucris.121387464,
abstract = {High energy x-ray diffraction measurements of lattice strains were performed on a rhombohedral Lead Zirconate Titanate ceramic (PZT 55-45) under combinations of applied electric field and compressive stress. These measurements allow the construction of blocking stress curves for different sets of crystallographic orientations which reflect the single crystal elastic anisotropy. A micro-mechanical interpretation of the results is then proposed. Assuming cubic symmetry for the crystalline elastic stiffness tensor and isotropy for the macroscopic elastic properties, the elastic properties of the single crystal are extracted from the measured data. An anisotropy ratio close to 0.3 is found (compared to 1 for isotropic materials). The high level of anisotropy found in this work suggests that crystalline elastic anisotropy should not be neglected in the modelling of ferroelectric materials. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.},
author = {Daniel, L. and Hall, D. A. and Webber, Kyle Grant and King, A. and Withers, P. J.},
doi = {10.1063/1.4874222},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Identification} of crystalline elastic anisotropy in {PZT} ceramics from in-situ blocking stress measurements},
volume = {115},
year = {2014}
}
@article{faucris.209901769,
abstract = {The piezoelectric coefficient is a measure to quantify the potential use of a material in energy harvesting and sensor applications. High concentration of free charge carriers in piezoelectric materials can significantly impede the use of generated piezoelectric charge. In this study, undoped semiconducting ZnO single crystals with both Ohmic and Schottky contacts were prepared to quantify the effective piezoelectric response at temperatures from 20 degrees C to -140 degrees C and frequencies of mechanical loading from 0.5 Hz to 160 Hz. It was demonstrated that the formation of an electrostatic potential barrier at the metal-semiconductor interface increases the overall resistance, which provides access to unbiased piezoelectric coefficients of ZnO single crystals even at room temperature. These findings were verified using semiconducting ZnO for energy harvesting at room temperature and relatively low loading frequency. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Novak, Nikola and Keil, Peter and Froemling, Till and Schader, Florian and Martin, Alexander and Webber, Kyle Grant and Roedel, Juergen},
doi = {10.1016/j.actamat.2018.10.008},
faupublication = {yes},
journal = {Acta Materialia},
keywords = {Semiconductor;Piezoelectricity;Piezotronics;Energy harvesting},
month = {Jan},
pages = {277-283},
peerreviewed = {Yes},
title = {{Influence} of metal/semiconductor interface on attainable piezoelectric and energy harvesting properties of {ZnO}},
volume = {162},
year = {2019}
}
@article{faucris.296112291,
abstract = {Composites based on ferroelectric Na0.5K0.5NbO3 (NKN) and paraelectric Al2O3 were observed using impedance spectroscopy at different temperatures. This allowed for the evaluation of the conduction processes of the bulk and grain boundary, revealing the occurrence of interdiffusion and changes in the conductive properties. The effective conductivity decreased with the increase in Al2O3, which is due to the highly resistive nature of Al2O3. Interestingly, the activation energy for the bulk response increased from 0.87 +/- 0.06 eV to approximately 1.12 +/- 0.03 eV, and the activation energy of the grain boundary decreased from 1.26 +/- 0.09 eV to 0.99 +/- 0.09 eV. These observations of the activation energy revealed the interdiffusion of Al3+ ions, leading to the formation of oxygen vacancies in close vicinity to the grain boundary. As a result, the conduction path for charge carriers shifted to take place predominantly along the grain boundary.},
author = {Martin, Alexander and Webber, Kyle Grant and Kakimoto, Keni-Chi},
doi = {10.3390/cryst13030463},
faupublication = {yes},
journal = {Crystals},
note = {CRIS-Team WoS Importer:2023-04-14},
peerreviewed = {Yes},
title = {{Influence} of {Oxygen} {Vacancies} on the {Impedance} {Spectrum} of {Al2O3}-{Na0}.{5K0}.{5NbO3} {Composites}},
volume = {13},
year = {2023}
}
@article{faucris.281723852,
abstract = {The influence of stress on the phase boundaries of polycrystalline lead-free perovskite (1 - x)Ba(Zr0.2Ti0.8)O-3-x(Ba0.7Ca0.3)TiO3 (x = 0.4, 0.5, and 0.6) was characterized through the temperature- and stress-dependent small-signal dielectric and piezoelectric response from - 150 to 200 degrees C under uniaxial compressive stress up to - 75 MPa. For all three compositions, the phase transition temperatures separating the rhombohedral, orthorhombic, tetragonal, and cubic phases were shifted to higher temperatures with an increase in the uniaxial mechanical loading, corresponding to a significant decrease in the dielectric and piezoelectric responses. Additional stress-dependent relative permittivity measurements up to - 260 MPa were conducted at four different constant temperatures (- 10, 10, 25, and 40 degrees C), revealing significant increases in the dielectric response, making these materials interesting for tunable dielectric applications. Furthermore, the stress-induced shift in phase transition temperatures was confirmed by in situ combined temperature- and stress-dependent Raman spectroscopy measurements under different constant uniaxial loads within the temperature range from 30 to 130 degrees C.},
author = {Gadelmawla, Ahmed and Dobesh, David and Eckstein, Udo and Grübl, Oliver and Ehmke, Matthias and Cicconi, Maria Rita and Khansur, Neamul Hayet and de Ligny, Dominique and Webber, Kyle Grant},
doi = {10.1007/s10853-022-07685-9},
faupublication = {yes},
journal = {Journal of Materials Science},
note = {CRIS-Team WoS Importer:2022-09-16},
peerreviewed = {Yes},
title = {{Influence} of stress on the electromechanical properties and the phase transitions of lead-free (1-x){Ba}({Zr0}.{2Ti0}.8){O}-3-x({Ba0}.{7Ca0}.3){TiO3}},
year = {2022}
}
@article{faucris.297269209,
abstract = {Tailoring the electromechanical properties of a material without altering the original composition is an emerging phenomenon for the optimization of functional properties. Post-sintering annealing with varying maximum temperatures, cooling rates, and atmospheres can influence the crystallographic phases, domain structures, conductivity, mechanical properties, and the temperature stability of the electromechanical properties. K1/2Bi1/2TiO3 (KBT) is a high-temperature stable >280 °C A-site complex perovskite piezoelectric and is critical for high-temperature applications. However, the influence of annealing conditions on crystal structure, domain structure, and functional properties is not well-known. This work demonstrates the effect of annealing cooling rate and maximum temperature on the macroscopic electromechanical response as well as the crystal and domain structure. It is shown that the room-temperature state of KBT can be reversibly switched between the ferroelectric and relaxor state, where the slow cooling from 900 °C favors the stabilization of the relaxor state and quenching induces the ferroelectric state. Importantly, the quenched sample showed a stable piezoelectric coefficient up to 368 °C in the depolarization temperature, an increase of 78 °C. The origin of ferroelectric-relaxor state change is proposed to be related to the A-site cation redistribution and the associated change in the crystal structure and domain structure.},
author = {Eyoum, Gina and Eckstein, Udo and Ursic, Hana and Pinto-Salazar, Monica and Buntkowsky, Gerd and Groszewicz, Pedro B. and Checchia, Stefano and Hayashi, Kouichi and Webber, Kyle Grant and Khansur, Neamul Hayet},
doi = {10.1039/d3ta00808h},
faupublication = {yes},
journal = {Journal of Materials Chemistry A},
note = {CRIS-Team Scopus Importer:2023-04-21},
peerreviewed = {Yes},
title = {{Influence} of temperature-induced {A}-site cation redistribution on the functional properties of {A}-site complex polar perovskite {K1}/{2Bi1}/{2TiO3}},
year = {2023}
}
@article{faucris.234631870,
abstract = {The macroscopic ferroelastic behavior of polycrystalline (La 0.6 Sr 0.4 ) 0.95 Co 0.2 Fe 0.8 O 3 − δ and its dependence on annealing conditions was investigated over a temperature range from −150 °C to 150 °C. A temperature- and defect concentration-dependent variation of the ferroelastic behavior was attributed to internal stresses, oxygen deficiency, and a corresponding change of the crystal structure. In particular, there was an observed decrease in remanent strain and the formation of a closed ferroelastic hysteresis loop at temperatures below approximately 0 °C for samples annealed in air, which was suppressed through the reduction in oxygen vacancies by annealing the samples in oxygen. The macroscopic mechanical behavior as a function of annealing conditions is discussed with respect to the crystal structure and oxygen deficiency determined by means of x-ray and neutron diffraction.},
author = {Rieß, Kevin and Geiger, Philipp and Khansur, Neamul Hayet and Steiner, Sebastian and Frömling, Till and Hinterstein, Manuel and Webber, Kyle Grant},
doi = {10.1016/j.mtla.2019.100297},
faupublication = {yes},
journal = {Materialia},
keywords = {Ferroelastic; Mechanical properties; Oxygen deficiency; Perovskite; X-ray diffraction (XRD)},
note = {CRIS-Team Scopus Importer:2020-02-21},
peerreviewed = {Yes},
title = {{Influence} of the annealing conditions on temperature-dependent ferroelastic behavior of {LSCF}},
volume = {6},
year = {2019}
}
@article{faucris.122254044,
abstract = {The dielectric behavior near the ferroelectric-to-paraelectric phase transition of < 001 >(C)-oriented single crystal and polycrystalline barium titanate (BaTiO3) was investigated as a function of uniaxial compressive stress in the temperature range from 25 to 200 degrees C. An increase in the Curie point (T-C) and decrease in the Curie-Weiss temperature (theta) were observed with increasing stress for both single crystal and polycrystalline samples, resulting in an increase in the first order nature of the phase transition as measured by the temperature difference (T-C - theta). With increasing applied stress levels, the permittivity versus temperature curves of polycrystalline samples were found to broaden and flatten near the Curie point, which was not observed for the single crystals. The experimental results were analyzed using a classical 2-4-6 Landau polynomial. The observed increase in the first order nature of the ferroelectric-to-paraelectric phase transition with uniaxial stress was explained by a linear dependence of the quartic coefficient of the Landau series on stress. (C) 2013 American Institute of Physics.},
author = {Schader, Florian H. and Aulbach, Emil and Webber, Kyle Grant and Rossetti, George A.},
doi = {10.1063/1.4799581},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Influence} of uniaxial stress on the ferroelectric-to-paraelectric phase change in barium titanate},
volume = {113},
year = {2013}
}
@article{faucris.267634896,
abstract = {External thermal, electrical, and mechanical fields can induce structural phase transitions in lead-free Li-modified Na0.5K0.5NbO3 ferroelectrics, which significantly influence the macroscopic electromechanical response. In particular, the relative stability of the polar monoclinic (or orthorhombic) and tetragonal phases under temperature and stress is critical to realize the ferroelectric and piezoelectric response. In this study, the effect of mechanical and thermal fields on the local structure in the vicinity of the monoclinic-tetragonal (M-T) phase boundary was investigated using a novel in situ combined uniaxial compressive stress- and temperature-dependent Raman spectroscopy experimental arrangement. Experiments were performed up to 300 degrees C and -200 MPa, clearly demonstrating stress-induced M-T phase transition in Li-modified Na0.5K0.5NbO3. A stress-temperature phase diagram has been established based on the change in vibrational modes. It was possible to correlate the relative permittivity singularities previously observed to a given stage of the M-T phase transition using ratio between characteristic Raman band areas. In addition, the measurement method reported here can be applied to other functional ceramics to investigate the influence of mechanical fields on local structure.},
author = {Khansur, Neamul Hayet and Eckstein, Udo and Bergler, Michael and Martin, Alexander and Wang, Ke and Li, Jing-Feng and Cicconi, Maria Rita and Hatano, Keiichi and Kakimoto, Ken-Ichi and de Ligny, Dominique and Webber, Kyle Grant},
doi = {10.1111/jace.18269},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
note = {CRIS-Team WoS Importer:2021-12-31},
peerreviewed = {Yes},
title = {{In} situ combined stress- and temperature-dependent {Raman} spectroscopy of {Li}-doped ({Na},{K}){NbO3}},
year = {2021}
}
@article{faucris.122630904,
abstract = {
Despite the technological importance of hard and soft PZT, Pb(Zr,Ti)O3, ceramics, the mechanisms of ferroelectric hardening and softening remain widely discussed in the literature. The hardening and softening phenomena have traditionally been investigated in relation with dielectric manifestations such as aging of the dielectric susceptibility and constriction of the polarization- electric field hysteresis loop. Here, we present a systematic investigation of the ferroelectric and ferroelastic properties of soft and hard PZT in both the tetragonal and rhombohedral phases. A par- ticular focus has been devoted to ferroelastic domain switching by characterizing the macroscopic mechanical constitutive behavior and in-situ synchrotron X-ray diffraction during compression. It is demonstrated that variation of the ordering state of point defects in PZT ceramics affects the switching behavior of both ferroelectric and ferroelastic domains under mechanical or electrical fields. Softening of the mechanical and electrical properties of originally hard PZT ceramics was conferred by quenching the materials from above the Curie temperature. The present findings are discussed with respect to the current understanding of hardening-softening transitions in ferroelec- tric materials.
},
author = {Morozov, Maxim and Einarsrud, Mari-Ann and Tolchard, Julian R. and Geiger, Philipp and Webber, Kyle Grant and Damjanovic, Dragan and Grande, Tor},
doi = {10.1063/1.4934615},
faupublication = {yes},
journal = {Journal of Applied Physics},
pages = {164104},
peerreviewed = {Yes},
title = {{In}-situ structural investigations of ferroelasticity in soft and hard rhombohedral and tetragonal {PZT}},
volume = {118},
year = {2015}
}
@article{faucris.123372304,
abstract = {Miniaturization of domains to the nanometer scale has been previously reported in many piezoelectrics with two-phase coexistence. Despite the observation of nanoscale domain configuration near the polymorphic phase transition (PPT) regionin virgin (K-0.5,Na-0.5)NbO3 (KNN) based ceramics, it remains unclear how this domain state responds to external loads and influences the macroscopic electromechanical properties. To this end, the electric -field -induced and stress -induced strain curves of KNNbased ceramics over a wide compositional range across PPT were characterized. It was found that the coercive field of the virgin samples was highest in PPT region, which was related to the inhibited domain wall motion due to the presence of nanodomains. However, the coercive field was found to be the lowest in the PPT region after electrical poling. This was related to the irreversible transformation of the nanodomains into micron -sized domains during the poling process. With the similar micron -sized domain configuration for all poled ceramics, the domains in the PPT region move more easily due to the additional polarization vectors. The results demonstrate that the poling process can give rise to the irreversible domain configuration transformation and then account for the inverted macroscopic piezoelectricity in the PPT region of KNN-based ceramics.},
author = {Huan, Yu and Wang, Xiaohui and Koruza, Jurij and Wang, Ke and Webber, Kyle Grant and Hao, Yanan and Li, Longtu},
doi = {10.1038/srep22053},
faupublication = {yes},
journal = {Scientific Reports},
peerreviewed = {Yes},
title = {{Inverted} electro-mechanical behaviour induced by the irreversible domain configuration transformation in ({K},{Na}){NbO3}-based ceramics},
volume = {6},
year = {2016}
}
@article{faucris.276701247,
abstract = {Ceramic-ceramic composite structures are a viable solution to improve the electromechanical response of lead-free ferroelectrics (FEs) through tuning of the local electrical and mechanical fields. The origin of the enhanced properties, however, remains unclear, as many of the possible effects, such as polarization and strain coupling (PSC) as well as interface diffusion, are interrelated and difficult to separate or directly investigate. In this study, we use a custom-built digital image correlation system to directly investigate the influence of strain coupling on 2-2 composites consisting of 0.90Na(1/2)Bi(1/2)TiO(3)-0.06BaTiO(3)-0.04K(0.5)Na(0.5)NbO(3) (NBT-6BT-4KNN) and 0.94Na(1/2)Bi(1/2)TiO(3)-0.06BaTiO(3) (NBT-6BT) by varying the mechanical interface contacts between end members. Specifically, two model cases were utilized to separate the relative contributions of the PSC mechanisms: (a) electrically connected and (b) mechanically and electrically connected. The local strain gradient was characterized through the thickness of the composite across different layers as well as the interface, where the macroscopic large signal longitudinal and transverse FE response was determined. Experimental results reveal an enhancement of the large signal piezoelectric coefficient d33* 3 (BCZT) and paraelectric Ca(Zr,Ti)O3 (CZT) are carried out by X-ray fluorescence holography. The images of the cations at the A and B sites of these ABO3 perovskites are clearly reconstructed from the measured holograms. In the real space images, a 0.2 Å outward displacement of the nearest Ba and Ca is observed in the atomic images of both BCZT and CZT, attributable to the difference in the ionic radius between Zr4+ and Ti4+. In addition, the first-neighboring Ti in BCZT is displaced inward by 0.5 Å, whereas no such displacement is observed in CZT. This shift of Ti in BCZT appears due to the large strain of the local lattice, and it can affect to the piezoelectric response of BCZT.},
author = {Yamamoto, Yuta and Kimura, Koji and Gadelmawla, Ahmed and Kawamura, Keisuke and Sugimoto, Hina and Liu, Donglin and Li, Qiang and Yan, Qingfeng and Khansur, Neamul Hayet and Happo, Naohisa and Kakimoto, Ken-Ichi and Webber, Kyle Grant and Hayashi, Kouichi},
doi = {10.1002/pssb.202100609},
faupublication = {yes},
journal = {physica status solidi (b)},
keywords = {ferroelectric materials; piezoelectric materials; X-ray fluorescence holography},
note = {CRIS-Team Scopus Importer:2022-04-15},
peerreviewed = {Yes},
title = {{Local} {Structural} {Investigation} of ({Ba},{Ca})({Zr},{Ti}){O3} and {Ca}({Zr},{Ti}){O3} by {X}-{Ray} {Fluorescence} {Holography}},
year = {2022}
}
@article{faucris.119562344,
abstract = {The temperature-dependent Young's modulus Y(T) of the lead-free piezoceramics of 0.8Bi(1/2)Na(1/2)TiO(3)-0.2Bi(1/2)K(1/2)TiO(3) (20BKT) and 0.96(0.8Bi(1/2)Na(1/2)TiO(3)-0.2Bi(1/2)K(1/2)TiO(3))-0.04 BiZn1/2Ti1/2O3 (4BZT) is measured with the impulse excitation technique and contrasted with corresponding dielectric and structural data. While the dielectric properties suggest a phase transition, the high resolution XRD patterns remain virtually unchanged from room temperature up to high temperatures, confirming no change in their long-range order. In contrast, the elastic properties indicate a broad and diffuse ferroelastic transition denoted by a minimum in Y(T). By analogy to the elastic and dielectric data of PbZrxTi1-xO3 and PLZT, it is concluded that 20BKT and 4BZT are relaxors with polar nanoregions embedded in a metrically cubic matrix. Interestingly, no indication for the freezing temperature was reflected in any of the employed measurement techniques. From the saturation of Y(T), it is suggested that the Burns temperature may be approximated as 700 degrees C. Moreover, it is found that the modification with the ternary end-member BiZn1/2Ti1/2O3 results in an increase in Young's modulus. A comparison with the Bi1/2Na1/2TiO3-BaTiO3-K0.5Na0.5NbO3 yields the same results. (C) 2014 AIP Publishing LLC.},
author = {Dittmer, Robert and Jo, Wook and Webber, Kyle Grant and Jones, Jacob L. and Rödel, Jürgen},
doi = {10.1063/1.4866092},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Local} structure change evidenced by temperature-dependent elastic measurements: {Case} study on {Bi1}/{2Na1}/{2TiO3}-based lead-free relaxor piezoceramics},
volume = {115},
year = {2014}
}
@article{faucris.263547392,
abstract = {A fully electromechanically coupled, three dimensional phenomenological constitutive model for relaxor ferroelectric materials was developed for the use in a finite-element-method (FEM) solution procedure. This macroscopic model was used to simulate the macroscopic electromechanical response of lead-free ergodic 0.94Na(1/2)Bi(1/2)TiO(3) -0.06BaTiO(3) and non-ergodic 0.90Na(1/2)Bi(1/2)TiO(3) - 0.06BaTiO(3) - 0.04K(0.5)Na(0.5)NbO(3) relaxor materials. The presented constitutive model is capable of accounting for the observed pinched hysteretic response as well as non-deviatoric polarization induced strain and internal order transitions. Time integration of the history dependent internal variables is done with a predictor-corrector integration scheme. The adaptability of the constitutive model regarding the pinching of the hystereses is shown. Simulations are compared to experimental observations.},
author = {Streich, Friedemann A. and Martin, Alexander and Webber, Kyle Grant and Kamlah, Marc},
doi = {10.1177/1045389X211038680},
faupublication = {yes},
journal = {Journal of Intelligent Material Systems and Structures},
note = {CRIS-Team WoS Importer:2021-09-03},
peerreviewed = {Yes},
title = {{Macroscopic} constitutive model for ergodic and non-ergodic lead-free relaxors},
year = {2021}
}
@article{faucris.111568864,
abstract = {The critical fracture toughness is a material parameter describing the resistance of a cracked body to further crack extension. It is an important parameter for simulating and predicting the breakup behavior of ice shelves from the calving of single icebergs to the disintegration of entire ice shelves over a wide range of length scales. The fracture toughness values are calculated with equations that are derived from an elastic stress analysis. Additionally, an X-ray computer tomography (CT scanner) was used to identify the density as a function of depth. The critical fracture toughness of 91 Antarctic bubbly ice samples with densities between 840 and 870 kg m(-3) has been determined by applying a four-point bending technique on single-edge v-notched beam samples. The examined ice core was drilled 70m north of Kohnen Station, Dronnning Maud Land (75 degrees 00' S, 00 degrees 04' E; 2882 m). Supplementary data are available at doi: 10.1594/PANGAEA.835321.},
author = {Christmann, J. and Mueller, R. and Webber, Kyle Grant and Isaia, D. and Schader, F. H. and Kipfstuhl, S. and Freitag, J. and Humbert, A.},
doi = {10.5194/essd-7-87-2015},
faupublication = {no},
journal = {Earth System Science Data},
month = {Jan},
pages = {87-92},
peerreviewed = {Yes},
title = {{Measurement} of the fracture toughness of polycrystalline bubbly ice from an {Antarctic} ice core},
volume = {7},
year = {2015}
}
@article{faucris.281183872,
abstract = {To increase the power output of piezoelectric energy harvesters, there are several options that have been the focus in a number of scientific studies. This work explores a new concept, by using ceramic/ceramic composites (Na0.55K0.45NbO3 + 0.2% MnO/Al2O3) for energy harvesting applications. The idea of increasing the elastic properties to maintain a sufficient power output is used. Mechanical and electrical properties of these composites with varying Al2O3 content have been evaluated to determine the energy harvesting properties. Here, the measured power densities exceeded the predicted values with a decrease from 0.11 mu W mm(-3) at 0 vol% to approximately 0.09 mu W mm(-3) between 5 and 15 vol%. Observations on the dielectric, piezoelectric and elastic properties revealed a residual stress inside the piezoelectric matrix. Whereas residual stress had a negative effect on the piezoelectric properties due to domain clamping and direct measurements of the energy harvesting properties showed a positive enhancement.},
author = {Martin, Alexander and Webber, Kyle Grant and Kakimoto, Ken-Ichi},
doi = {10.35848/1347-4065/ac85f7},
faupublication = {yes},
journal = {Japanese Journal of Applied Physics},
note = {CRIS-Team WoS Importer:2022-09-02},
peerreviewed = {Yes},
title = {{Mechanical} and electrical properties of {Na0}.{55K0}.{45NbO3}+0.2% {MnO}/{Al2O3} composites for energy harvesting applications},
volume = {61},
year = {2022}
}
@article{faucris.109617024,
abstract = {The free strain during unipolar electrical activation and the blocking stress are important figures of merit for actuator applications. The lead-free (1 - x)Ba(Zr0.2Ti0.8)O-3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) system has been shown to display exceptional unipolar strain at room temperature, making it very attractive as an electroactive material for large displacement, low frequency actuation systems. In this work, the temperature-and composition-dependent blocking stress is measured with the proportional loading method. It was found that BZT-xBCT outperformed Pb(Zr1-xTix)O-3 and Bi1/2Na1/2TiO3-based ceramics for electric fields up to 2 kV/mm. (C) 2014 AIP Publishing LLC.},
author = {Brandt, David RJ and Acosta, Matias and Koruza, Jurij and Webber, Kyle Grant},
doi = {10.1063/1.4879395},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Mechanical} constitutive behavior and exceptional blocking force of lead-free {BZT}-{xBCT} piezoceramics},
volume = {115},
year = {2014}
}
@article{faucris.111504844,
abstract = {The structural origin of the mechanical double loop behavior of polycrystalline BaTiO3 at temperatures just above the Curie point has been investigated using in situ high-energy synchrotron x-ray diffraction during uniaxial compressive mechanical loading. The results show a stress-induced transition from the high temperature paraelastic cubic phase to a ferroelastic tetragonal phase with a domain texture close to the saturated state. The nature of the observed stress-induced phase transition was influenced by the proximity of the temperature to the Curie point. With increasing temperature above the Curie point, the transition stress increased while the rate of the transition decreased. (C) 2013 AIP Publishing LLC.},
author = {Daniels, John E. and Picht, Gunnar and Kimber, Simon and Webber, Kyle Grant},
doi = {10.1063/1.4821446},
faupublication = {no},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Mechanical} double loop behavior in {BaTiO3}: {Stress} induced paraelastic to ferroelastic phase transformation},
volume = {103},
year = {2013}
}
@article{faucris.122299364,
abstract = {
The influence of uniaxial compressive stress on the small signal direct piezoelectric coefficient of hard and soft Pb(Zr,Ti)O3 at the morphotropic phase boundary was investigated as a function of temperature from 25 °C to 450 °C. The stress- and temperature-dependent piezoelectric data indi- cate that stress is capable of either directly or indirectly modifying the orientation of polar defects in the crystal lattice and reduce the internal bias field. At higher temperatures, the mobility of polar defects was found to increase, corresponding to a two-step decrease in the direct piezoelectric coef- ficient and a decrease in the frequency dispersion. Quenching experiments were used to elucidate the role of the internal bias field on the stress-dependent piezoelectric response.
},
author = {Schader, Florian H. and Morozov, Maxim and Wefring, Espen and Grande, Tor and Webber, Kyle Grant},
doi = {10.1063/1.4919815},
faupublication = {no},
journal = {Journal of Applied Physics},
pages = {194101},
peerreviewed = {Yes},
title = {{Mechanical} stability of piezoelectric properties in ferroelectric perovskites},
volume = {117},
year = {2015}
}
@article{faucris.273933620,
abstract = {The miniaturization of electronic devices and power systems requires the fabrication of functional components in the form of micrometer-sized thick films. A major challenge is the integration of functional ceramics with metals, which are considered incompatible with high-temperature ceramic processing. To overcome the integration barrier, an aerosol deposition (AD) spray-coating method based on room temperature deposition can be used. By employing the AD method, we were able to deposit relaxor-ferroelectric 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 ceramic thick films on low-cost stainless-steel substrates. The as-deposited films were dense, with ∼97% of the theoretical density. Moreover, the post-deposition annealing at 500 °C did not result in any microstructural changes. Compared to the as-deposited films, the annealed films exhibit improved energy storage and electromechanical properties. The annealed thick films achieve a recoverable energy density of 15.1 J·cm-3 at an electric field of 1350 kV·cm-1 and an electric-field cycling stability of 5 million cycles. A piezoelectric response was detected through the entire film thickness by piezoelectric force microscopy. Macroscopic displacement measurements revealed a maximum relative strain of 0.38% at 1000 kV·cm-1, corresponding to inverse effective piezoelectric coefficient of ∼40 pm·V-1. In this study, we overcame the integration challenges and demonstrated the multifunctionalization of future ceramic-metal structures, as the deposited thick films on stainless steel exhibit energy storage capability and piezoelectric properties. },
author = {Sadl, Matej and Nadaud, Kevin and Bah, Micka and Levassort, Franck and Eckstein, Udo and Khansur, Neamul Hayet and Webber, Kyle Grant and Ursic, Hana},
doi = {10.1088/2515-7655/ac5fd5},
faupublication = {yes},
journal = {JPhys Energy},
keywords = {aerosol deposition; energy storage; multifunctional; piezoelectric; PMN-PT; stainless steel},
note = {CRIS-Team Scopus Importer:2022-04-29},
peerreviewed = {Yes},
title = {{Multifunctional} energy storage and piezoelectric properties of 0.{65Pb}({Mg1}/{3Nb2}/3){O3}-0.{35PbTiO3thick} films on stainless-steel substrates},
volume = {4},
year = {2022}
}
@article{faucris.120042824,
author = {Ayrikyan, Azatuhi and Weyland, Florian and Steiner, Sebastian and Duerrschnabel, Michael and Molina-Luna, Leopoldo and Koruza, Jurij and Webber, Kyle Grant},
doi = {10.1111/jace.14887},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
keywords = {Composites; Ferroelectricity/ferroelectric materials; Laminates; Piezoelectric materials/properties; Sinter/sintering},
peerreviewed = {Yes},
title = {{Multilayer} lead-free piezoceramic composites: {Influence} of co-firing on microstructure and electromechanical behavior},
year = {2017}
}
@article{faucris.122530584,
abstract = {Perovskite type Ba0.5Sr0.5Co0.8Fe0.2O3 (- delta) ceramics display nonlinear stress-strain behaviour upon uniaxial compression at room temperature. Step functional loading experiments show that the nonlinear strain response of the material is time dependent, partially reversible and depends on the oxygen vacancy concentration. In situ compressive stress-dependent synchrotron X-ray diffraction reveals that the nonlinearity is not related to ferroelasticity or a stress-induced phase transformation. The oxygen vacancy concentration and average spin state were determined from Rietveld analysis of the magnetic scattering found in the neutron powder diffraction data, indicating their role during mechanical loading. An oxygen vacancy migration model and a spin-state transition are proposed as possible mechanisms of nonlinear mechanical response. (C) 2016 Elsevier B.V. All rights reserved.},
author = {Geiger, Philipp T. and Clemens, Oliver and Khansur, Neamul Hayet and Hinterstein, Manuel and Sahini, Mtabazi G. and Grande, Tor and Tung, Patrick and Daniels, John E. and Webber, Kyle Grant},
doi = {10.1016/j.ssi.2016.11.027},
faupublication = {yes},
journal = {Solid State Ionics},
pages = {106-113},
peerreviewed = {Yes},
title = {{Nonlinear} mechanical behaviour of {Ba0}.{5Sr0}.{5Co0}.{8Fe0}.{2O3} (- delta) and in situ stress dependent synchrotron {X}-ray diffraction study},
volume = {300},
year = {2017}
}
@article{faucris.121151404,
abstract = {Temperature-dependent stress-strain behavior of various soft Pb0.98Ba0.01(Zr1-x Ti-x)(0.98)Nb0.02O3, 0.40 <= x <= 0.60, compositions was characterized between 25 and 400 degrees C to determine the influence of crystal structure on ferroelasticity. The ferroelastic response was found to depend significantly on the crystal phase as well as the spontaneous strain, both of which varied with temperature. The remanent strain for rhombohedral materials was shown to be above the theoretical maximum allowed by the crystal spontaneous strain. This observed behavior indicates the presence of hysteretic processes in addition to ferroelasticity during mechanical compression. A phenomenological free energy analysis was used to predict the effects of stress on the stable phase in ferroelectrics and indicates the susceptibility of the rhombohedral and tetragonal structure to a stress-induced phase transition. Modeling results indicate the relative importance of such phase transitions on macroscopic stress-strain behavior, giving an indirect method to observe field-induced phase transitions in polycrystalline ferroelectrics. DOI: 10.1103/PhysRevB.87.094116},
author = {Seo, Yo-Han and Franzbach, Daniel J. and Koruza, Jurij and Bencan, Andreja and Malic, Barbara and Kosec, Marija and Jones, Jacob L. and Webber, Kyle Grant},
doi = {10.1103/PhysRevB.87.094116},
faupublication = {no},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Nonlinear} stress-strain behavior and stress-induced phase transitions in soft {Pb}({Zr1}-{xTix}){O}-3 at the morphotropic phase boundary},
volume = {87},
year = {2013}
}
@article{faucris.318372495,
abstract = {This study investigates bilayers of 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3 (NBT-6BT) and 0.90(Na1/2Bi1/2)TiO3-0.06BaTiO3-0.04(K0.5Na0.5)NbO3 (NBT-6BT-4KNN) using digital image correlation, enabling the separate analysis of strain response in each layer. The bilayers were electrically connected without mechanical connection (polarization coupled) as well as mechanically and electrically connected (polarization and strain coupled) to determine the role of interlayer mechanical interactions. The large signal longitudinal and transverse piezoelectric coefficients, d 33 ∗ and d 31 ∗ , were characterized for both cases. In the polarization coupled composite, d 33 ∗ decreased linearly from 410 to 260 pm/V with increasing vol. % NBT-6BT. In contrast, in the polarization and strain coupled case, d 33 ∗ and d 31 ∗ were maximum at 50 vol. % NBT-6BT with values of 440 and −130 pm/V, respectively, highlighting the critical role of strain interactions in ceramic-ceramic composites. The stress-induced phase transformation through strain coupling significantly impacted the electromechanical response, with improved strain values observed in the NBT-6BT-4KNN layer. Furthermore, this study highlights the variability in the significance of strain coupling within bilayer systems as a function of the altering volume fraction of their constituent components.},
author = {Martin, Alexander and Maier, Juliana and Kakimoto, Ken Ichi and Kamlah, Marc and Webber, Kyle Grant},
doi = {10.1063/5.0184763},
faupublication = {yes},
journal = {Journal of Applied Physics},
month = {Jan},
note = {CRIS-Team Scopus Importer:2024-02-16},
peerreviewed = {Yes},
title = {{Observation} of the local electromechanical response in 2-2 ceramic-ceramic lead-free ferroelectric composites via digital image correlation},
volume = {135},
year = {2024}
}
@article{faucris.111505504,
abstract = {The large-signal unipolar behavior of PZT is characterized under combined electrical, thermal, and mechanical loading. Maximum strain S-max and polarization P-max feature a pronounced sensitivity on stress with a field-dependent peak evolving at around -50 MPa that is associated with enhanced non-180 degrees domain switching. As notable strains are achieved in excess of the quasi-statically measured blocking stress, it is suggested that the testing procedure presented within this work is suited to supplement blocking force measurements in order to comprehensively evaluate the electromechanical performance of a piezoceramic. With the suppression of non-180 degrees domain switching at high stress levels, S-max(sigma) decreases at a faster rate than P-max(sigma). Accordingly, the electrostrictive coefficient Q(11) is shown to be stress-dependent. This observation is rationalized with the stress-dependent change of domain processes. It is furthermore found that Q(11) features a notable dependence on temperature, increasing from 0.018 m(4) C-2 at 25 degrees C to 0.028 m(4) C-2 at 150 degrees C under zero-stress. To assess the actuatoric efficiency, a novel figure of merit eta* is defined to quantify the fraction of input energy utilized for mechanical work. (C) 2012 Elsevier B.V. All rights reserved.},
author = {Dittmer, Robert and Webber, Kyle Grant and Aulbach, Emil and Jo, Wook and Tan, Xiaoli and Rödel, Jürgen},
doi = {10.1016/j.sna.2012.09.015},
faupublication = {no},
journal = {Sensors and Actuators A-Physical},
keywords = {Lead-zirconate-titanate;PZT;Stress dependence;Working regime;Temperature dependence;Actuator;Electrostriction;Polarization losses;Efficiency},
month = {Jan},
pages = {187-194},
peerreviewed = {Yes},
title = {{Optimal} working regime of lead-zirconate-titanate for actuation applications},
volume = {189},
year = {2013}
}
@article{faucris.120081764,
author = {Menge, Georg and Lorenz, Hannes and Fu, Zongwen and Eichhorn, Franziska and Schader, Florian and Webber, Kyle Grant and Fey, Tobias and Greil, Peter and Travitzky, Nahum},
doi = {10.1002/adem.201800052},
faupublication = {yes},
journal = {Advanced Engineering Materials},
keywords = {Microstructure; Multilayer BaTiO3; Piezoelectric properties; Preceramic paper},
peerreviewed = {unknown},
title = {{Paper}-{Derived} {Ferroelectric} {Ceramics}: {A} {Feasibility} {Study}},
year = {2018}
}
@article{faucris.119719204,
abstract = {Limited reliability of ferroelectric-based actuators restricts their use in high-performance applications, where stress-induced cracking of ferroelectric ceramics often leads to fatal failure. The main limiting factors are the relatively small fracture toughness and the brittle nature of ferroelectrics. However, ferroelectrics naturally exhibit fracture toughening (so called ferroelastic toughening) due to stress induced reorientation of non-180 degrees domains that inhibits crack propagation. Here we present a phase-field study of ferroelastic toughening based on Landau-Ginzburg-Devonshire theory. The primary qualitative factors that control the magnitude of ferroelastic toughening are identified and discussed. (c) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Sluka, Tomas and Webber, Kyle Grant and Colla, Enrico and Damjanovic, Dragan},
doi = {10.1016/j.actamat.2012.06.023},
faupublication = {no},
journal = {Acta Materialia},
keywords = {Ferroelectricity;Toughness;Fracture;Phase field models;Simulation},
pages = {5172-5181},
peerreviewed = {Yes},
title = {{Phase} field simulations of ferroelastic toughening: {The} influence of phase boundaries and domain structures},
volume = {60},
year = {2012}
}
@article{faucris.212708757,
abstract = {The interface coupling effect of multilayer lead-free ceramic/ceramic relaxor/ferroelectric composites is studied by finite element-based phase-field simulations. The macroscopic electromechanical behavior of such composite systems is influenced by both polarization and strain coupling through the electrical and mechanical interaction of connected layers. Separating such interconnected phenomena is difficult experimentally. Here, we direct investigate different coupling effect by introducing soft and charge interphase layers in the serial-type layer composite model. The large strain response of the composite results from the electric field- induced nonpolar-polar phase transition of the relaxor constituent. A new relaxor phase-field model is first developed to reproduce this phase transition and parameterized by fitting the measured hysteresis loops. It is then directly compared to the experimental results of the serial-type composite composed of 0.91Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3)-0.03AgNbO(3) and 0.93Bi(1/2)Na(1/2)TiO(3)-0.07BaTiO(3). Results show that the lateral strain coupling in the serial layer contributes considerably to the large signal piezoelectric coefficient d(33)* The primary enhancement in d(33)* is due a reduction in the remanent strain of the ferroelectric layer caused by the lateral mismatch. Moreover, charge interphase layers in the composite can introduce an internal electric field, leading to a weaker large-signal response compared with the composite with coherent interfaces.},
author = {Wang, Shuai and Ayrikyan, Azatuhi and Zhang, Haibo and Webber, Kyle Grant and Xu, Bai-Xiang},
doi = {10.1002/aelm.201800710},
faupublication = {yes},
journal = {Advanced Electronic Materials},
note = {CRIS-Team WoS Importer:2019-03-08},
peerreviewed = {Yes},
title = {{Phase}-{Field} {Study} of {Electromechanical} {Coupling} in {Lead}-{Free} {Relaxor}/{Ferroelectric}-{Layered} {Composites}},
volume = {5},
year = {2019}
}
@article{faucris.124126464,
abstract = {Electric-field-and stress-induced phase transformations were investigated in polycrystalline 0.5 mol. % Mn-doped (1-x)(Bi1/2Na1/2)TiO3-x(Bi1/2K1/2)TiO3 (x = 0.1, 0.2). To characterize the effect of electric field and stress on the stability of the ferroelectric and relaxor states, polarization- and current density-electric field curves, as well as the stress-strain response as a function of temperature were characterized. Analogous to the observed electrical behavior, the macroscopic mechanical constitutive behavior showed a closed hysteresis at elevated temperatures, indicating a reversible stress-induced relaxor-to-ferroelectric transformation. The electrical and mechanical measurements were used to construct electric field-temperature and stress-temperature phase diagrams, which show similar characteristics. These data show that a mechanical compressive stress, similarly to an electric field, can induce long-range ferroelectric order in a relaxor ferroelectric. Published by AIP Publishing.},
author = {Ehara, Yoshitaka and Novak, Nikola and Ayrikyan, Azatuhi and Geiger, Philipp and Webber, Kyle Grant},
doi = {10.1063/1.4966614},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Phase} transformation induced by electric field and mechanical stress in {Mn}-doped ({Bi1}/{2Na1}/2){TiO3}-({Bi1}/{2K1}/2){TiO3} ceramics},
volume = {120},
year = {2016}
}
@article{faucris.119102104,
abstract = {The relative permittivity of polycrystalline BaTiO3 was measured from -150 degrees C to 250 degrees C at compressive bias stresses up to -500 MPa. Mechanical loading shifted the rhombohedral-orthorhombic, orthorhombic-tetragonal, and tetragonal-cubic phase transition temperatures and produced a pronounced broadening of the dielectric softening in the vicinity of all three transitions. The inter-ferroelectric rhombohedral-orthorhombic and orthorhombic-tetragonal phase transitions were found to be less stress sensitive than the ferroelectric-paraelectric transition occurring between tetragonal and cubic phases at the Curie point. The application of compressive stress resulted in a strong suppression of the relative permittivity, such that at the highest applied stress of -500 MPa, the permittivity in the single phase regions away from the phase transitions was found to display only a weak dependence on temperature between -100 degrees C and 125 degrees C. The experimental observations closely followed the predictions of a 2-4-6 Landau polynomial wherein the dielectric stiffness and higher-order dielectric stiffness coefficients are linear functions of uniaxial stress. Published by AIP Publishing.},
author = {Schader, Florian H. and Khakpash, Nasser and Rossetti, George A. and Webber, Kyle Grant},
doi = {10.1063/1.4976060},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Phase} transitions in {BaTiO3} under uniaxial compressive stress: {Experiments} and phenomenological analysis},
volume = {121},
year = {2017}
}
@article{faucris.123557544,
abstract = {The direct piezoelectric coefficient and permittivity of < 001 > c-0.26Pb(In1/2Nb1/2)O-3-0.47Pb(Mg1/3Nb2/3) O-3-0.27PbTiO(3) (PIN-PMN-PT) single crystals were simultaneously measured as functions of temperature and uniaxial compressive stress at various frequencies. The results show a nonlinear increase of the piezoelectric coefficient from similar to 1300 pC/N at 25 degrees C to over 8000 pC/N at 99 degrees C, followed by a sharp decrease and gradual decay to zero. The peak in piezoelectric coefficient coincides with a dielectric anomaly that is associated with a rhombohedral to tetragonal phase transition. An increase of the compressive bias stress reduced the magnitude of the peak in piezoelectric coefficient and shifted it to lower temperatures, revealing an initial increase in the piezoelectric response understood to be due to a stress-induced phase transition. The large-signal macroscopic constitutive behavior was characterized at various compressive stresses from 25 degrees C to 150 degrees C. These data are contrasted with the small-signal piezoelectric measurements and show the combined influence of stress and temperature on the electromechanical properties and stress-induced phase transitions in relaxor ferroelectric PIN-PMN-PT single crystals. Implications of the results for the application window of single-crystal PIN-PMN-PT transducers are discussed. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Schader, Florian H. and Rossetti, George A. and Luo, Jun and Webber, Kyle Grant},
doi = {10.1016/j.actamat.2016.12.051},
faupublication = {yes},
journal = {Acta Materialia},
keywords = {Ferroelecric;Relaxor;Single crystal;Piezoelectric},
pages = {174-181},
peerreviewed = {Yes},
title = {{Piezoelectric} and ferroelectric properties of < 001 > c {Pb}({In1}/{2Nb1}/2) {O}-3-{Pb}({Mg1}/{3Nb2}/3){O}-3-{PbTiO3} single crystals under combined thermal and mechanical loading},
volume = {126},
year = {2017}
}
@article{faucris.242211428,
abstract = {The multiferroic nature of the honeycomb-lattice Mn2V2O7 was investigated through detailed temperature, high-pressure, and magnetic-field-dependent measurements. A first-order martensiticlike structural phase transition with the thermal hysteresis associated with magnetic, heat-capacity, and dielectric anomalies was observed between T-Mh (303 K) and T-Mc (291 K). External pressure up to 15.41 kbar suppresses the thermal hysteresis in the magnetization data, indicating that the high-temperature beta-phase persists down to the lower temperature under 15.41 kbar. Furthermore, isothermal capacitance-stress hysteresis loops along with crystallographic Aizu notation of 2/mF (1) over bar supports a martensitic phase transition driving ferroelastic ordering near or below room temperature. At low temperature, a long-range antiferromagnetic ordering was observed at T-N similar to 17 K. With increasing the external pressure up to 15.41 kbar, 100% enhancement of T-N was observed and a metamagnetic transition at 5 K was enhanced near 3 T. High-field magnetization study up to 60 T induces multiple metamagnetic transitions below T-N. Below T-N, a magnetostriction induced magnetoelectric coupling was observed and further supported by the temperature-dependent x-ray studies. Taking these comprehensive research findings into account, we established that Mn2V2O7 is a unique multifunctional material with the coexistence of ferroelastic and antiferromagnetic orderings and with weak magnetoelectric coupling.},
author = {Wu, H. C. and Hsieh, D. J. and Yen, T. W. and Sun, P. J. and Kakarla, D. Chandrasekhar and Her, J. L. and Matsuda, Y. H. and Chang, C. K. and Lai, Y. C. and Gooch, M. and Deng, L. Z. and Webber, Kyle Grant and Lee, C. A. and Chou, Mitch M. C. and Chu, C. W. and Yang, H. D.},
doi = {10.1103/PhysRevB.102.075130},
faupublication = {yes},
journal = {Physical Review B},
note = {CRIS-Team WoS Importer:2020-09-04},
peerreviewed = {Yes},
title = {{Pressure} and magnetic field effects on ferroelastic and antiferromagnetic orderings in honeycomb-lattice {Mn2V2O7}},
volume = {102},
year = {2020}
}
@article{faucris.119456084,
abstract = {The crack growth resistance behavior of single crystal and polycrystalline 0.71Pb(Mg1/3Nb2/3)O-3-0.29PbTiO(3) (PMN-29% PT) was determined with compact-tension specimens. Two different single crystal orientations were produced by the solid-state crystal growth technique (SSCG) and characterized, allowing for the direct comparison to polycrystalline material. Single crystal R-curve behavior was observed to be anisotropic, which is explained by the effects of ferroelasticity and stress-induced phase transformations on toughening. Results of the polycrystalline samples display comparable toughness to that observed in single crystal measurements.},
author = {Webber, Kyle Grant and Seo, Yo-Han and Lee, Ho-Yong and Aulbach, Emil and Jo, Wook and Rödel, Jürgen},
doi = {10.1111/j.1551-2916.2011.04677.x},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {2728-2730},
peerreviewed = {Yes},
title = {{R}-{Curve} {Behavior} of {Pb}({Mg1}/{3Nb2}/3){O}-3-29 mol% {PbTiO3} {Single} {Crystals}: {The} {Effect} of {Crystallographic} {Orientation} and {Grain} {Structure}},
volume = {94},
year = {2011}
}
@article{faucris.111572824,
abstract = {Composites from lead zirconate titanate (PZT) and yttria stabilized zirconia were manufactured to assess cracking and R-curve behavior in compact tension specimens. Additions of zirconia led to a reduction in PZT grain size and shifted the fracture behavior from intergranular fracture to intragranular fracture. The R-curves exhibited higher starting values, a steeper slope and a higher plateau value with increasing content of zirconia, albeit the effects on the toughness values were not more than 20%. The results are rationalized through increased crack tip toughness, reduced ferroelastic toughening and enhanced transformation toughening. (C) 2012 Elsevier Ltd. All rights reserved.},
author = {Rödel, Jürgen and Seo, Yo-Han and Bencan, Andreja and Malic, Barbara and Kosec, Marija and Webber, Kyle Grant},
doi = {10.1016/j.engfracmech.2012.06.023},
faupublication = {no},
journal = {Engineering Fracture Mechanics},
keywords = {Lead zirconate titanate;Ferroelasticity;Transformation toughening;R-curve;Microstructure},
pages = {86-91},
peerreviewed = {Yes},
title = {{R}-curves. in transformation toughened lead zirconate titanate},
volume = {100},
year = {2013}
}
@article{faucris.119936344,
abstract = {Recently developed lead-free incipient piezoceramics are promising candidates for off-resonance actuator applications with their exceptionally large electromechanical strains. Their commercialization currently faces two major challenges: high electric field required for activating the large strains and large strain hysteresis. It is demonstrated that design of a relaxor/ferroelectric composite provides a highly effective way to resolve both challenges. Experimental results in conjunction with numerical simulations provide key parameters for the development of viable incipient piezoceramics.},
author = {Groh, Claudia and Franzbach, Daniel J. and Jo, Wook and Webber, Kyle Grant and Kling, Jens and Schmitt, Ljubomira Ana and Kleebe, Hans-Joachim and Jeong, Soon‐Jong and Lee, Jae-Shin and Rödel, Jürgen},
doi = {10.1002/adfm.201302102},
faupublication = {no},
journal = {Advanced Functional Materials},
keywords = {relaxor;ceramic-ceramic composites;actuators;lead-free piezoceramics},
month = {Jan},
pages = {356-362},
peerreviewed = {Yes},
title = {{Relaxor}/{Ferroelectric} {Composites}: {A} {Solution} in the {Quest} for {Practically} {Viable} {Lead}-{Free} {Incipient} {Piezoceramics}},
volume = {24},
year = {2014}
}
@article{faucris.118106164,
author = {Hagiwara, Manabu and Ehara, Yoshitaka and Novak, Nikola and Khansur, Neamul Hayet and Ayrikyan, Azatuhi and Webber, Kyle Grant and Fujihara, Shinobu},
doi = {10.1103/PhysRevB.96.014103},
faupublication = {yes},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Relaxor}-ferroelectric crossover in ({B} i1/2 {K1}/2){Ti} {O3}: {Origin} of the spontaneous phase transition and the effect of an applied external field},
volume = {96},
year = {2017}
}
@article{faucris.120082204,
author = {Koruza, Jurij and Bell, Andrew J. and Frömling, Till and Webber, Kyle Grant and Wang, Ke and Rödel, Jürgen},
doi = {10.1016/j.jmat.2018.02.001},
faupublication = {yes},
journal = {Journal of Materiomics},
keywords = {Actuators; Application; Ferroelectrics; Lead-free; Piezoceramics; Sensors},
pages = {13-26},
peerreviewed = {Yes},
title = {{Requirements} for the transfer of lead-free piezoceramics into application},
volume = {4},
year = {2018}
}
@article{faucris.217716321,
abstract = {Aerosol deposition is a feasible method of fabricating dense ceramic
films at room temperature by the impact consolidation of submicron‐sized
particles on ceramic, metal, glass, and polymer substrates at a rapid
rate. Despite the potential usefulness of the aerosol deposition
process, there are issues, such as deposition mechanisms and structure
of the film‐substrate interface, that are not well understood. We have
used complementary structural and microstructural analysis to capture
the state of the substrate surface after the aerosol deposition process.
The results reveal that modification of the substrate surface by the
ejected submicron‐sized particles is essential for the formation of
anchoring layer, thereby, a change in internal residual stress state and
surface free energy of the substrate is required to deposit film using
AD process. Our analysis also suggests that the adhesion between the
metal substrate and ceramic particles is possibly contributed by both
physical bonding and mechanical interlocki},
author = {Khansur, Neamul H. and Eckstein, Udo and Li, Yizhe and Hall, David A. and Kaschta, Joachim and Webber, Kyle Grant},
doi = {10.1111/jace.16489},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
keywords = {stress; thick films; X-ray methods},
peerreviewed = {Yes},
title = {{Revealing} the effects of aerosol deposition on the substrate-film interface using {NaCl} coating},
url = {https://ceramics.onlinelibrary.wiley.com/doi/abs/10.1111/jace.16489},
year = {2019}
}
@article{faucris.216919710,
abstract = {Aerosol deposition is a feasible method of fabricating dense ceramic films at room
temperature by the impact consolidation of submicron‐sized particles on ceramic,
metal, glass, and polymer substrates at a rapid rate. Despite the potential usefulness
of the aerosol deposition process, there are issues, such as deposition mechanisms
and structure of the film‐substrate interface, that are not well understood. We have
used complementary structural and microstructural analysis to capture the state of the
substrate surface after the aerosol deposition process. The results reveal that modification
of the substrate surface by the ejected submicron‐sized particles is essential
for the formation of anchoring layer, thereby, a change in internal residual stress
state and surface free energy of the substrate is required to deposit film using AD
process. Our analysis also suggests that the adhesion between the metal substrate and
ceramic particles is possibly contributed by both physical bonding and mechanical
interlocking.
ferroelectrics over the past decade. Under certain conditions, the electromechanical properties of some compositions now match or even surpass commercially available lead-containing materials over a wide temperature range, making them potentially attractive for non-resonant displacement applications. However, the phenomena responsible for the large unipolar strains and piezoelectric responses can be markedly different to classical ferroelectrics such as Pb(Zr,Ti)O3 and BaTiO3. Despite the promising electromechanical properties, there is little understanding of the mechanical properties and fracture behavior, which is crucial for their implementation into applications where they will be exposed to large electrical, mechanical, and thermal fields. This work discusses and reviews the current understanding of the mechanical behavior of large-strain perovskite lead-free ferroelectrics for use in actuators and provides recommendations for further work in this important field.},
author = {Webber, Kyle Grant and Voegler, Malte and Khansur, Neamul Hayet and Kaeswurm, Barbara and Daniels, John E. and Schader, Florian},
doi = {10.1088/1361-665X/aa590c},
faupublication = {yes},
journal = {Smart Materials and Structures},
keywords = {ferroelasticity; ferroelectricity; lead-free ferroelectrics; mechanical properties; relaxors},
peerreviewed = {Yes},
title = {{Review} of the mechanical and fracture behavior of perovskite lead-free ferroelectrics for actuator applications},
volume = {26},
year = {2017}
}
@article{faucris.120200124,
abstract = {The blocking force test is a standard test to characterise the properties of piezoelectric actuators. The aim of this study is to understand the various contributions to the macroscopic behaviour observed during this experiment that involves the intrinsic piezoelectric effect, ferroelectric domain switching, and internal stress development. For this purpose, a high energy diffraction experiment is performed in-situ during a blocking force test on a tetragonal lead zirconate titanate (PZT) ceramic (Pb0.98Ba0.01(Zr0.51Ti0.49)(0.98)Nb0.02O3). It is shown that the usual macroscopic linear interpretation of the test can also be performed at the single crystal scale, allowing the identification of local apparent piezoelectric and elastic properties. It is also shown that despite this apparent linearity, the blocking force test involves significant non-linear behaviour mostly due to domain switching under electric field and stress. Although affecting a limited volume fraction of the material, domain switching is responsible for a large part of the macroscopic strain and explains the high level of inter-and intra-granular stresses observed during the course of the experiment. The study shows that if apparent piezoelectric and elastic properties can be identified for PZT single crystals from blocking stress curves, they may be very different from the actual properties of polycrystalline materials due to the multiplicity of the physical mechanisms involved. These apparent properties can be used for macroscopic modelling purposes but should be considered with caution if a local analysis is aimed at. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.},
author = {Daniel, L. and Hall, D. A. and Koruza, J. and Webber, Kyle Grant and King, A. and Withers, P. J.},
doi = {10.1063/1.4918928},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Revisiting} the blocking force test on ferroelectric ceramics using high energy x-ray diffraction},
volume = {117},
year = {2015}
}
@article{faucris.279018031,
abstract = {The room temperature aerosol deposition method is especially promising for the rapid deposition of ceramic thick films, making it interesting for functional components in energy, mobility, and telecommunications applications. Despite this, a number of challenges remain, such as an enhanced electrical conductivity and internal residual stresses in as-deposited films. In this work, a novel technique that integrates a sacrificial water-soluble buffer layer was used to fabricate freestanding ceramic thick films, which allows for direct observation of the film without influence of the substrate or prior thermal treatment. Here, the temperature-dependent chemical and structural relaxation phenomena in freestanding BaTiO3 films were directly investigated by characterizing the thermal expansion properties and temperature-dependent crystal structure as a function of oxygen partial pressure, where a clear nonlinear, hysteretic contraction was observed during heating, which is understood to be influenced by lattice defects. As such, aliovalent doping and atmosphere-dependent annealing experiments were used to demonstrate the influence of local chemical redistribution and oxygen vacancies on the thermal expansion, leading to insight into the origin of the high room temperature conductivity of as-deposited films as well as greater insight into the influence of the induced chemical, structural, and microstructural changes in room temperature deposited functional ceramic thick films.},
author = {Eckstein, Udo and Khansur, Neamul Hayet and Bergler, Michael and Urushihara, Daisuke and Asaka, Toru and Kakimoto, Ken-Ichi and Sadl, Matej and Dragomir, Mirela and Ursic, Hana and de Ligny, Dominique and Webber, Kyle Grant},
doi = {10.1007/s10853-022-07467-3},
faupublication = {yes},
journal = {Journal of Materials Science},
note = {CRIS-Team WoS Importer:2022-07-29},
peerreviewed = {Yes},
title = {{Room} temperature deposition of freestanding {BaTiO3} films: temperature-induced irreversible structural and chemical relaxation},
year = {2022}
}
@article{faucris.204032423,
abstract = {In various practical applications, such as high power actuators, high sensitivity sensors, and energy harvesting devices, polycrystalline piezoelectric films of 1-100 mu m thickness and sizes ranging from several mu m(2) to several cm(2) are required. With conventional film deposition processes, such as sol-gel, sputtering, chemical vapor deposition, or pulsed laser deposition, it is difficult to fabricate films with higher thickness due to their low deposition rate and high interfacial stress. The aerosol deposition method (AD), a relatively new deposition technique, can be used to fabricate highly dense thick films at room temperature by the consolidation of sub micrometer-sized ceramic particles on various ceramic, metal, glass, and polymer substrates. Ferroelectric BaTiO3 ceramic films of different thicknesses ranging from 1 to 30 gm were fabricated on a low-cost metallic substrate at room temperature using the AD method. Surface morphology and adhesion of the film were analyzed. Analysis of internal residual stresses revealed an equibiaxial compressive stress state in the as-processed film. Electrical characterization of films annealed at 500 degrees C shows an enhanced polarization value of similar to 14 mu C/cm(2) over that of the as-processed film. This improved property is related to the decreasing internal residual stress. In addition, the BT films prepared in this work were found to withstand electric fields greater than 100 kV/mm, which is possibly related to the inherent relatively defect-free structure of AD films.},
author = {Khansur, Neamul Hayet and Eckstein, Udo and Benker, Lisa and Deisinger, Ulrike and Merle, Benoit and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2018.06.027},
faupublication = {yes},
journal = {Ceramics International},
keywords = {Functional ceramics;Aerosol deposition;Internal stress;Thick films},
pages = {16295-16301},
peerreviewed = {Yes},
title = {{Room} temperature deposition of functional ceramic films on low-cost metal substrate},
volume = {44},
year = {2018}
}
@article{faucris.269465658,
abstract = {The x-ray fluorescence holography technique is applied to perovskite (Ba0.9Ca0.1)TiO3 ferroelectrics in order to investigate the local structures around the Ca and Ba ions at the A-site. While the A-site atomic images around the Ba ion can be well understood based on the BaTiO3 structure, those around the Ca ion are located at the closer positions to the emitter. Furthermore, the shape of the atomic image around the Ca ion is elongated in the radial direction. These features clearly show the local lattice contraction around the Ca ion and a significant displacement of the Ca ions from the ideal position. On the basis of the detailed analysis of the position and the shape of the atomic image around the Ca ion, it is found that the Ca ions are displaced by & SIM;0.36 & ANGS; in the & lang; 111 & rang; direction, and the surrounding Ba ions are displaced by & SIM;0.22 & ANGS; in the & lang;100 & rang; direction. The present results indicate that the doped Ca ions activate the A-site polarization of this compound, which can lead to an enhancement of the ferroelectric and piezoelectric performances.},
author = {Yamamoto, Y. and Kawamura, K. and Sugimoto, H. and Gadelmawla, Ahmed and Kimura, K. and Happo, N. and Tajiri, H. and Webber, Kyle Grant and Kakimoto, K. and Hayashi, K.},
doi = {10.1063/5.0076325},
faupublication = {yes},
journal = {Applied Physics Letters},
month = {Jan},
note = {CRIS-Team WoS Importer:2022-02-11},
peerreviewed = {Yes},
title = {{Significant} displacement of calcium and barium ions in ferroelectric ({Ba0}.{9Ca0}.1){TiO3} revealed by x-ray fluorescence holography},
volume = {120},
year = {2022}
}
@article{faucris.111479764,
abstract = {The influence of second phase zirconia particles on the electrical properties and fracture behavior of various polycrystalline soft Pb(Zr1-xTix)O-3 (PZT) compositions was investigated. PZT composites with yttria-stabilized tetragonal zirconia particles exhibited enhanced crack resistance in comparison to monolithic compositions, regardless of the PZT composition. The addition of zirconia, however, was found to change the PZT composition through the diffusion of zirconium, resulting in variations in the observed piezoelectric and ferroelectric responses. Through the tailoring of the PZT matrix composition, the large electromechanical response and enhanced fracture toughness could be retained. The variation in both small and large signal properties is contrasted to fracture results and crystal structure changes, as determined by X-ray diffraction.},
author = {Seo, Yo-Han and Koruza, Jurij and Bencan, Andreja and Malic, Barbara and Rödel, Jürgen and Webber, Kyle Grant},
doi = {10.1111/jace.12929},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {1582-1588},
peerreviewed = {Yes},
title = {{Simultaneous} {Enhancement} of {Fracture} {Toughness} and {Unipolar} {Strain} in {Pb}({Zr},{Ti}){O}-3-{ZrO2} {Composites} {Through} {Composition} {Adjustment}},
volume = {97},
year = {2014}
}
@article{faucris.281181523,
abstract = {Sintering conditions govern the optimized functional properties of ceramics. However, solid-state processing of Bi1/2K1/2TiO3 (BKT), an important end member for lead-free piezoelectric solid solutions suitable for higher temperature (<= 300 degrees C) transducer applications, is challenging due to the low melting temperature (approximate to 1070 degrees C). In this work, the sintering temperature (1030 degrees C, 1050 degrees C, and 1060 degrees C) and dwell time (10 h, 20 h, and 40 h)-dependent functional properties of solid-state processed BKT were investigated, where the sintering condition-dependent dielectric and electromechanical properties were correlated with the variations in crystal structure and microstructure. Although X-ray diffraction data revealed a single-phase tetragonal structure of BKT at room temperature for all sintering conditions, significant changes in both the tetragonal distortion and spontaneous relaxor-ferroelectric transition were observed, which were directly related to the optimized functional properties. In addition, Rayleigh behavior of the piezoelectric coefficient was characterized between -150 degrees C and 400 degrees C, demonstrating that the electromechanical response is dominated by the intrinsic contribution, which can be explained by large tetragonal distortion and associated suppression of non-180 degrees domain wall motion.},
author = {Eyoum, Gina and Eckstein, Udo and Rieß, Kevin and Gadelmawla, Ahmed and Springer, Eva and Webber, Kyle Grant and Khansur, Neamul Hayet},
doi = {10.1007/s10853-022-07630-w},
faupublication = {yes},
journal = {Journal of Materials Science},
note = {CRIS-Team WoS Importer:2022-09-02},
peerreviewed = {Yes},
title = {{Sintering} condition-dependent electromechanical behavior of the lead-free piezoelectric {Bi1}/{2K1}/{2TiO3}},
year = {2022}
}
@article{faucris.255352820,
abstract = {Despite the importance of (Na1/2Bi1/2)TiO3 as an end member in lead-free ferroelectrics and as an oxide ion conductor, the relaxor/ferroelectric nature remains unclear. In order to understand the relaxor-like behavior, frequency-dependent macroscopic mechanical measurements of polycrystalline (Na1/2Bi1/2)TiO3 were performed as a function of poling state, revealing the role of a potential field-induced long-range ferroelectric order on the nonlinear hysteretic stress-strain behavior. The mechanical measurements showed an increase in remanent strain and decrease in coercive stress with electrical poling, consistent with previous studies of relaxors. Electrical poling and mechanical texturing were found to influence the frequency dispersion of the relative permittivity, highlighting the potentially relaxor-like response. Further, the relative permittivity showed a directional dependence with respect to the previously applied electrical and mechanical fields. These data are discussed in conjunction with ex situ stress- and electric-field-dependent piezoresponse force microscopy measurements that revealed a clear ferroelectric domain switching through the application of a sufficiently high electric field, but no change of the domain configuration for uniaxial compressive stresses up to -750 MPa. The in situ stress-dependent crystal structure, which was characterized using synchrotron x-ray diffraction, however, indicates stress-induced ferroelastic domain switching as the primary hysteretic process.},
author = {Rieß, Kevin and Khansur, Neamul Hayet and Martin, Alexander and Benčan, Andreja and Uršič, Hana and Webber, Kyle Grant},
doi = {10.1103/PhysRevB.103.094113},
faupublication = {yes},
journal = {Physical Review B},
note = {CRIS-Team Scopus Importer:2021-04-16},
peerreviewed = {Yes},
title = {{Stress}- {And} frequency-dependent properties of relaxor-like sodium bismuth titanate},
volume = {103},
year = {2021}
}
@article{faucris.120082864,
author = {Geiger, Philipp and Khansur, Neamul Hayet and Rieß, Kevin and Martin, Alexander and Hinterstein, Manuel and Webber, Kyle Grant},
doi = {10.1063/1.5017934},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Stress}-dependent crystal structure of lanthanum strontium cobalt ferrite by in situ synchrotron {X}-ray diffraction},
volume = {123},
year = {2018}
}
@article{faucris.122260864,
abstract = {The effect of 1 at% Fe- and FeNb-doping on the temperature and stress stability of the electromechanical properties of (Ba1-xCax)(ZryTi1-y)O-3 (BCZT) was investigated. For the composition (Ba0.89Ca0.11)(Zr0.135Ti0.865)O-3 with rhombohedral symmetry, doping reduces the Curie point and the temperature stability of the large-signal electromechanical properties significantly. The large-signal piezoelectric coefficient d(33)* at room temperature was reduced to 500 pm/V compared to 700 pm/V in the undoped composition at 1 kV/mm. The electrostrain, however, was found to be less sensitive to mechanical prestresses, showing a plateau up to stresses of 80 MPa in both doped compositions. These effects were attributed to a reduction of the domain wall mobility due to a smaller grain size, charged defect dipoles and the proximity of the room-temperature measurements to the reduced ferroelectric-paraelectric phase transition temperature. The study reveals that the exceptionally large strains observed in BCZT rely on the instabilities around the polymorphic phase transition in the system. Aliovalent doping changes this sensitive system and reduces the electrostrain considerably. (C) 2014 Elsevier Ltd. All rights reserved.},
author = {Humburg, Heide I. and Acosta, Matias and Jo, Wook and Webber, Kyle Grant and Roedel, Juergen},
doi = {10.1016/j.jeurceramsoc.2014.10.016},
faupublication = {no},
journal = {Journal of the European Ceramic Society},
keywords = {BZT-BCT;Doping;Piezoelectric properties;Lead-free;Ferroelasticity},
pages = {1209-1217},
peerreviewed = {Yes},
title = {{Stress}-dependent electromechanical properties of doped ({Ba1}-{xCax})({ZryTi1}-y){O}-3},
volume = {35},
year = {2015}
}
@article{faucris.310439847,
abstract = {In this study, stress-dependent impedance spectra were characterized as a function of uniaxial compressive stress up to -300 MPa for Zr-doped (Na0.5K0.5)(Nb1−x/125Zrx/100)O3−δ (x = 5, 10 mol%). This allowed for the evaluation of the stress-induced changes in the grain and grain boundary capacitance. The grain capacitance from equivalent circuit fitting exhibited decreasing behavior with increasing uniaxial compressive stress increased, which is attributed to hindered domain wall movement reducing the extrinsic contributions. Interestingly, NKNZ10 showed a more significant degradation in grain capacitance than NKNZ5. One possible explanation is the difference in oxygen vacancies, and by extension defect dipoles, when introducing Zr into the lattice. As such, this study reveals the amplifying effect of oxygen vacancies to the mechanical suppression of domain wall movement.},
author = {Tanaka, Hideki and Nozaki, Takumi and Martin, Alexander and Webber, Kyle Grant and Kakimoto, Ken Ichi},
doi = {10.35848/1347-4065/acedb8},
faupublication = {yes},
journal = {Japanese Journal of Applied Physics},
keywords = {defect dipole; ferroelasticity; lead free ferroelectrics; stress dependent impedance spectroscopy},
note = {CRIS-Team Scopus Importer:2023-09-15},
peerreviewed = {Yes},
title = {{Stress} dependent impedance spectroscopy of niobium based ceramics},
volume = {62},
year = {2023}
}
@article{faucris.111510784,
abstract = {High-temperature piezoelectric polycrystalline ceramics of the system (1 - x)(Bi1-yLay)FeO3-xPbTiO(3) (BF-PT), which are mixed phase in their consolidated state, have been investigated by in situ neutron diffraction during the application of uniaxial compressive stress. It is suggested that the achievable strain in BF-PT is largely generated by straining of the rhombohedral phase. The results of the neutron diffraction measurements are compared and discussed with respect to the measured macroscopic ferroelastic constitutive behavior for various compositions of BF-PT. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd All rights reserved.},
author = {Leist, Thorsten and Webber, Kyle Grant and Jo, Wook and Aulbach, Emil and Roedel, Juergen and Prewitt, Anderson D. and Jones, Jacob L. and Schmidlin, Josh and Hubbard, Camden R.},
doi = {10.1016/j.actamat.2010.07.012},
faupublication = {no},
journal = {Acta Materialia},
keywords = {Piezoelectricity;Ferroelectncity;Neutron diffraction},
pages = {5962-5971},
peerreviewed = {Yes},
title = {{Stress}-induced structural changes in {La}-doped {BiFeO3}-{PbTiO3} high-temperature piezoceramics},
volume = {58},
year = {2010}
}
@article{faucris.308494748,
abstract = {In this study, the stress-modulated energy storage properties of lead-free polycrystalline Ba0.85Ca0.15Zr0.1Ti0.9O3 was investigated as a function of temperature from 25 °C to 55 °C. The externally applied uniaxial compressive stress of −160 MPa increased the recoverable energy storage density by 226% to a maximum value of 274 mJ/cm3, in addition to enhancing the energy storage efficiency by approximately 10% to a value of 88.2%. The macroscopic mechanical constitutive behavior is presented as well as the stress-dependent dielectric and ferroelectric properties and the Rayleigh behavior in order to elucidate the effect of stress on the energy storage properties. Importantly, the stress-induced tailoring of energy storage performance can be utilized for other nonlinear dielectric ceramics to tune their extrinsic polarization mechanisms to significantly enhance the recoverable energy density and reduce the hysteretic losses.},
author = {Maier, Juliana and Gadelmawla, Ahmed and Khansur, Neamul Hayet and Webber, Kyle Grant},
doi = {10.1016/j.jmat.2022.12.010},
faupublication = {yes},
journal = {Journal of Materiomics},
keywords = {Energy storage; Ferroelectric; Lead-free; Polarization mechanism; Rayleigh behavior; Stress-dependent},
note = {Created from Fastlane, Scopus look-up},
pages = {673-682},
peerreviewed = {Yes},
title = {{Stress}-induced tailoring of energy storage properties in lead-free {Ba0}.{85Ca0}.{15Zr0}.{1Ti0}.{9O3} ferroelectric bulk ceramics},
volume = {9},
year = {2023}
}
@article{faucris.241260356,
abstract = {The effect of uniaxial compressive stress on the crystal structure of a 6 mol. % Li-doped (K,Na)NbO3 (LKNN6a) ceramic was investigated using in situ synchrotron X-ray diffraction, revealing the stress-induced relative change in monoclinic Pm and tetragonal P4mm phases. As such, stress-induced phase transformations, in addition to the lattice deformation and domain switching, are the contributing factors for the observed macroscopic mechanical behavior of LKNN6a. The in situ stress-dependent diffraction data also demonstrates a method to mechanically modulate the polymorphic phase transition temperature (TPPT) to a higher temperature, as observed by the temperature-dependent permittivity measurements under a constant bias stress. The external uniaxial compressive stress increases the stability of the lower symmetry monoclinic phase, shifting TPPT to a higher temperature by 60 °C for the maximum uniaxial compressive stress of 300 MPa in the studied composition. Importantly, the stress-induced stabilization of the room-temperature ferroelectric phase can be useful to optimize the phase transition region, as well as increase the temperature stability of lead-free KNN. },
author = {Khansur, Neamul Hayet and Martin, Alexander and Rieß, Kevin and Nishiyama, Hiroshi and Hatano, Keiichi and Wang, Ke and Li, Jing Feng and Kakimoto, Ken Ichi and Webber, Kyle Grant},
doi = {10.1063/5.0016072},
faupublication = {yes},
journal = {Applied Physics Letters},
note = {CRIS-Team Scopus Importer:2020-08-07},
peerreviewed = {Yes},
title = {{Stress}-modulated optimization of polymorphic phase transition in {Li}-doped ({K},{Na}){NbO3}},
volume = {117},
year = {2020}
}
@article{faucris.122482404,
abstract = {The effect of external mechanical fields on relaxor 0.94(Na1/2Bi1/2) TiO3-0.06BaTiO(3) was investigated by means of temperature-and stress-dependent dielectric constant measurements between 223 and 673 K. Analogous to previous investigations that showed an electric-field-induced ferroelectric long-range order in relaxor ferroelectrics, we show that compressive stress can also result in the transition to the long-range ferroelectric order, marked by the formation of an anomaly in the permittivity-temperature curves and a nonlinear, remanent change in permittivity during mechanical loading. In situ stress-dependent high-energy x-ray diffraction experiments were performed at room temperature and reveal an apparent phase transition during mechanical loading, consistent with previous macroscopic electrical measurements. The transition lines between the relaxor states and the stress-induced ferroelectric state were determined at constant temperatures with stress-dependent dielectric constant measurements, providing a stress-temperature phase diagram.},
author = {Schader, Florian H. and Wang, Zhiyang and Hinterstein, Manuel and Daniels, John E. and Webber, Kyle Grant},
doi = {10.1103/PhysRevB.93.134111},
faupublication = {yes},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Stress}-modulated relaxor-to-ferroelectric transition in lead-free ({Na1}/{2Bi1}/2) {TiO3}-{BaTiO3} ferroelectrics},
volume = {93},
year = {2016}
}
@article{faucris.122260644,
abstract = {The large signal strain response as a function of uniaxial compressive stress, electric field and temperature is investigated for compositions across the morphotropic phase boundary in the (Ba,Ca)(Ti,Zr)O-3 ferroelectric system. The largest piezoelectric coefficient in terms of unipolar strain divided by the maximum applied field, S-u/E-max, is 1540 pm V-1, which clearly exceeds the piezoelectric response of most lead zirconate titanate materials. The extraordinarily large piezoelectric properties occur in the vicinity of the morphotropic phase boundary region on the rhombohedral side of the phase diagram. In this material, an electric threshold field is observed that is required to overcome the stress-induced domain clamping and obtain a measurable strain response. Moreover, the study reveals that careful selection of composition, stress and field amplitude allow for large signal piezoelectric coefficients of over 740 pm V-1 in the temperature range of 25-75 degrees C. The extraordinarily large unipolar strain response can be assigned to an electric field-controlled regime, in which the unipolar compressive stress induces non-180 degrees domain switching perpendicular to the applied electric field. During electrical loading, the electric field can realign these domains back into the parallel direction, maximizing non-180 degrees domain switching and enhancing unipolar strain. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Ehmke, Matthias C. and Schader, Florian H. and Webber, Kyle Grant and Roedel, Juergen and Blendell, John E. and Bowman, Keith J.},
doi = {10.1016/j.actamat.2014.06.005},
faupublication = {no},
journal = {Acta Materialia},
keywords = {BZT-BCT;Lead-free;Ferroelectrics;Actuator;Ferroelasticity},
pages = {37-45},
peerreviewed = {Yes},
title = {{Stress}, temperature and electric field effects in the lead-free ({Ba},{Ca})({Ti},{Zr}){O}-3 piezoelectric system},
volume = {78},
year = {2014}
}
@article{faucris.111511664,
abstract = {In this work, the effect of introducing tetragonal yttria-stabilized zirconia (TZ) particles in soft [Pb0.98Ba0.01][(Zr0.53Ti0.47)(0.98)Nb-0.02]O-3 (PZT) was investigated. Both microstructure and electrical properties of the PZT-xTZ (x = 0, 2, 5, 10, 20 vol%) composites were studied and correlated. The addition of zirconia hinders the matrix grain growth, resulting in smaller grains. According to X-ray diffraction analysis, zirconia containing composites have a higher rhombohedral-to-tetragonal phase ratio, in addition to lower dielectric and piezoelectric properties, in comparison to pure PZT. Electrical properties, in terms of strain- and polarization-electric field hysteresis curves, are presented and correlated with the observed phase compositions and microstructures. The extrinsic contribution to the piezoelectric properties in PZT and PZT-xTZ was studied by measuring the frequency and the stress field amplitude dependences of the piezoelectric d(33) coefficient.},
author = {Bencan, Andreja and Malic, Barbara and Drnovsek, Silvo and Tellier, Jenny and Rojac, Tadej and Pavlic, Jernej and Kosec, Marija and Webber, Kyle Grant and Roedel, Juergen and Damjanovic, Dragan},
doi = {10.1111/j.1551-2916.2011.04803.x},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {651-657},
peerreviewed = {Yes},
title = {{Structure} and the {Electrical} {Properties} of {Pb}({Zr},{Ti}){O}-3 - {Zirconia} {Composites}},
volume = {95},
year = {2012}
}
@article{faucris.209902037,
abstract = {The residual stress through the thickness of a BaTiO3 ceramic film deposited on steel substrate at room temperature with aerosol deposition has been analyzed using synchrotron x-ray microdiffraction. A gradient in stress distribution was evident through the film and the maximum biaxial compressive stress of -800 MPa was observed at the film-substrate interface. Heat-treatment was found to relax the internal compressive stress, due to thermal expansion mismatch between the film and substrate. Variation in ferroelectric response was correlated to the change in stress state by thermal treatment. This analysis is crucial for development of micro-and nanoelectronic devices with AD films. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Khansur, Neamul Hayet and Eckstein, Udo and Rieß, Kevin and Martin, Alexander and Drnec, Jakub and Deisinger, Ulrike and Webber, Kyle Grant},
doi = {10.1016/j.scriptamat.2018.07.045},
faupublication = {yes},
journal = {Scripta Materialia},
keywords = {Aerosol deposition;Ferroelectric materials;Ceramic films;Internal stresses;X-ray diffraction (XRD)},
pages = {86-89},
peerreviewed = {Yes},
title = {{Synchrotron} x-ray microdiffraction study of residual stresses in {BaTiO3} films deposited at room temperature by aerosol deposition},
volume = {157},
year = {2018}
}
@article{faucris.111480204,
abstract = {The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions. (C) 2014 AIP Publishing LLC.},
author = {Khansur, Neamul H. and Groh, Claudia and Jo, Wook and Reinhard, Christina and Kimpton, Justin A. and Webber, Kyle Grant and Daniels, John E. and Khansur, Neamul Hayet},
doi = {10.1063/1.4869786},
faupublication = {no},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Tailoring} of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach},
volume = {115},
year = {2014}
}
@article{faucris.287262718,
abstract = {The influence of stress on the small-signal dielectric permittivity and piezoelectric coefficient of polycrystalline lead-free perovskite 0.92(Na1/2K1/2)NbO3-(0.08 - x)Bi1/2Li1/2TiO3-xBaZrO(3) (x = 0, 0.02, 0.04, 0.06, and 0.07) was characterized under different constant uniaxial stress up to -200 MPa within a temperature range of -150 to 450 degrees C, revealing stress-induced suppression of the electromechanical response as well as shifts in the phase boundaries. For all compositions, the interferroelectric and ferroelectric-paraelectric phase transitions were shifted to higher temperatures under the uniaxial compressive stress. Interestingly, the sensitivity to the applied stress was found to increase with increasing BZ/BLT ratio in the system. The origin of a different extent of stress-sensitivity with BZ/BLT ratio is suggested to be related to the change in the crystal structure. Additionally, at temperatures below -50 degrees C, the relative permittivity showed a significant increase under applied compressive stress.},
author = {Gadelmawla, Ahmed and Eckstein, Udo and Rieß, Kevin and Liu, Yi-Xuan and Wang, Ke and Li, Jing-Feng and Kakimoto, Ken-Ichi and Khansur, Neamul Hayet and Webber, Kyle Grant},
doi = {10.1111/jace.18917},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
note = {CRIS-Team WoS Importer:2023-01-06},
peerreviewed = {Yes},
title = {{Temperature}- and stress-dependent electromechanical properties of phase-boundary-engineered {KNN}-based piezoceramics},
year = {2022}
}
@article{faucris.238712252,
abstract = {The small-signal direct piezoelectric coefficient and dielectric permittivity are characterized as a function of temperature from 25 to 450 °C and uniaxial compressive stress up to 80 MPa in porous Pb(Zr,Ti)O3 (PZT; 10, 20, 30, 40, and 50 vol% porosity). Results show retention of piezoelectric response throughout the temperature range with increasing porosity up to 30 vol%, above which a subsequent decrease is observed. Similarly, increasing porosity did not result in a significant change of the depolarization temperature, although a slight increase in the Curie point is observed with increasing porosity. Macroscopic experimental results are discussed together with microcomputed tomography, which shows the 3D pore structure. These results are important for sensing applications that operate at elevated temperatures and apply compressive stress to the electroactive element.},
author = {Khansur, Neamul Hayet and Biggemann, Jonas and Stumpf, Martin and Rieß, Kevin and Fey, Tobias and Webber, Kyle Grant},
doi = {10.1002/adem.202000389},
faupublication = {yes},
journal = {Advanced Engineering Materials},
keywords = {electromechanical properties; hydrostatic figure of merit; porous piezoelectric ceramics; transduction coefficients},
note = {CRIS-Team Scopus Importer:2020-05-26},
peerreviewed = {Yes},
title = {{Temperature}- and {Stress}-{Dependent} {Electromechanical} {Response} of {Porous} {Pb}({Zr},{Ti}){O3}},
year = {2020}
}
@article{faucris.203737950,
abstract = {The anhysteretic behavior of a soft Pb(Zr,Ti)O3 was measured from 25 C to 175 C. The
experimental determination of the anhysteretic polarization curve, combined with classical P-E and S-
E loop measurements, allows for an experimental separation of the reversible and dissipative
contributions to the ferroelectric behavior. This approach offers insight into the different mechanisms
originating at the microscopic scale and the contribution to the macroscopic ferroelectric properties. It
was found that the reversible anhysteretic susceptibility va of the unpoled material increases by 30%
from room temperature to 150 C. On the other hand, the effect on the total susceptibility for a null
polarization vc increases only by 17% over the same temperature range. Since the difference between
va and vc reflects the dissipative contribution to the macroscopic ferroelectric behavior, this reveals
that dissipation reduces the improvement of susceptibility under increasing temperature. This work
illustrates the benefits of separating experimentally the reversible and dissipative contributions to
describe the ferroelectric behavior, which can serve as a basis for advanced modeling approaches.
0.5Li0.5TiO3-0.06BaZrO3 was investigated. Results reveal that at room temperature, the intrinsic fracture toughness (KI0) of the unpoled samples, evaluated by the near-tip crack opening displacement (COD) technique, is the lowest with a value of 0.70 MPa⋅m0.5; the long (through-thickness) crack fracture toughness (KIvnb), obtained by the single edge V-notch beam (SEVNB) technique, is the highest, with a value of 0.95 MPa⋅m0.5; intermediate short surface crack fracture toughness (KIsc) of 0.86 MPa⋅m0.5 was determined by the surface crack in flexure (SCF) technique. These results were rationalized by the toughening behavior of the material combined with the crack geometry-dependent stress intensity evolution during crack propagation. With increasing temperature, KIvnb and KIsc decrease, and become nearly identical at 350 °C, suggesting an absence of toughening. For electrically poled samples, their room temperature fracture toughness was characterized by both SCF and SEVNB techniques, with values of 0.88 MPa⋅m0.5 and 0.99 MPa⋅m0.5, respectively, slightly larger than the values measured for unpoled samples. Nonlinear electric field-strain and stress-strain analysis of the material was also employed during electric field loading, mechanical compression and four-point bending in order to quantify crack tip shielding by domain switching and the actual stress at the point of instable crack propagation.},
author = {Li, Yingwei and Liu, Yixuan and Öchsner, Paul-Erich and Isaia, Daniel and Zhang, Yichi and Wang, Ke and Webber, Kyle Grant and Li, Jing Feng and Rödel, Jürgen},
doi = {10.1016/j.actamat.2019.05.060},
faupublication = {yes},
journal = {Acta Materialia},
keywords = {Domain switching; Fracture toughness; Lead-free piezoceramics; Potassium-sodium niobate; Toughening},
note = {CRIS-Team Scopus Importer:2019-06-18},
pages = {369-378},
peerreviewed = {Yes},
title = {{Temperature} dependent fracture toughness of {KNN}-based lead-free piezoelectric ceramics},
volume = {174},
year = {2019}
}
@article{faucris.124114804,
abstract = {The crack growth resistance behavior of polycrystalline Pb(Zr1-xTix)O-3 has been characterized in a novel experimental arrangement between 24 and 140 degrees C. Experimental measurements were carried out on compact tension specimens submerged in a temperature-controlled silicone oil bath. The results show a decrease in the observed shielding toughness, leading to an overall reduction in the maximum toughness. The temperature-dependent stress strain behavior and elastic properties were characterized, providing an insight into the effect of the changing ferroelastic properties on the temperature-dependent fracture behavior. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Seo, Yo-Han and Voegler, Malte and Isaia, Daniel and Aulbach, Emil and Roedel, Juergen and Webber, Kyle Grant},
doi = {10.1016/j.actamat.2013.07.020},
faupublication = {no},
journal = {Acta Materialia},
keywords = {Lead zirconate titanate;Temperature-dependent Fracture;R-curve;Ferroelastic toughening},
pages = {6418-6427},
peerreviewed = {Yes},
title = {{Temperature}-dependent {R}-curve behavior of {Pb}({Zr1}-{xTix}){O}-3},
volume = {61},
year = {2013}
}
@article{faucris.119742744,
abstract = {The temperature-dependent crack growth resistance behavior of the lead-free (1-x)Ba(Zr0.2Ti0.8)O-3-x(Ba0.7Ca0.3)TiO3 (x = 0.385) ceramic was characterized using compact-tension specimens from 25 degrees C to 60 degrees C. The observed plateau fracture toughness at 25 degrees C was found to be approximately 37% lower than commercial Pb(Zr,Ti)O-3. At elevated temperature, the maximum fracture toughness displayed a decrease, which was found to be related to the temperature-dependent elastic and ferroelastic properties. Mechanical measurements are presented that demonstrate decreasing effective switching strain, coercive stress and Young's modulus with increasing temperature. (C) 2015 Elsevier Ltd. All rights reserved.},
author = {Voegler, Malte and Acosta, Matias and Brandt, David R. J. and Molina-Luna, Leopoldo and Webber, Kyle Grant},
doi = {10.1016/j.engfracmech.2015.06.069},
faupublication = {no},
journal = {Engineering Fracture Mechanics},
keywords = {Fracture mechanics;Crack growth;R-curve;BZT-BCT;Ferroelasticity},
pages = {68-77},
peerreviewed = {Yes},
title = {{Temperature}-dependent {R}-curve behavior of the lead-free ferroelectric 0.{615Ba}({Zr0}.{2Ti0}.8){O}-3-0.385({Ba0}.{7Ca0}.3){TiO3} ceramic},
volume = {144},
year = {2015}
}
@article{faucris.271020746,
abstract = {Aerosol deposition (AD) is a room-temperature film deposition method for the fabrication of scalable ferroelectric ceramic films on different substrates, which is particularly appealing for thick film energy storage applications. However, the electrical and mechanical properties of AD ferroelectric films are not yet satisfactorily understood. Here, we report the dielectric, energy storage, and mechanical properties of aerosol-deposited BaTiO3 (AD-BT) thick films with nanosized grains by combining macroscopic electric measurements with indentation tests. We find that thermal annealing is an effective way to improve dielectric permittivity and polarization of the AD-BT film, as well as to increase the hardness and Young's modulus of the film. However, crack formation in the annealed AD-BT film is promoted in comparison to the as-processed sample, suggesting that the interplay between the nanosized grains and release of the internal stress during annealing may have major consequences for the mechanical properties and hence should be taken into consideration in application.},
author = {Zhuo, Fangping and Eckstein, Udo and Khansur, Neamul Hayet and Dietz, Christian and Urushihara, Daisuke and Asaka, Toru and Kakimoto, Ken-Ichi and Webber, Kyle Grant and Fang, Xufei and Roedel, Juergen},
doi = {10.1111/jace.18377},
faupublication = {yes},
journal = {Journal of the American Ceramic Society},
note = {CRIS-Team WoS Importer:2022-03-18},
peerreviewed = {Yes},
title = {{Temperature}-induced changes of the electrical and mechanical properties of aerosol-deposited {BaTiO3} thick films for energy storage applications},
year = {2022}
}
@article{faucris.120200784,
abstract = {The temperature dependence of piezoelectric properties (direct piezoelectric coefficient d(33), converse piezoelectric coefficient d(33)(E=0), strain S and electromechanical coupling coefficient k(p)) for two niobate-based lead-free piezoceramics have been contrasted. 0.92(Na0.5K0.5)NbO3-0.02(Bi1/2Li1/2)TiO3-0.06BaZrO(3) (6BZ/2BLT/92NKN) has a morphotropic phase boundary (MPB) between rhombohedral and tetragonal at room temperature and 0.92(Na0.5K0.5)NbO3-0.03(Bi1/2Li1/2)TiO3-0.05BaZrO(3) (5BZ/3BLT/92NKN) features an MPB engineered to be located below room temperature. At 30 degrees C, d(33),d(33)(E=0), S (at 2kV/mm), and k(p) are 252pC/N, 230pm/V, 0.069%, 0.51 for 5BZ/3BLT/92NKN; and 348pC/N, 380pm/V, 0.106%, 0.57 for 6BZ/2BLT/92NKN, respectively. With increasing temperature, the piezoelectric properties decrease. At 200 degrees C, d(33), d(33)(E=0), S (at 2kV/mm), and k(p) are 170pC/N, 160pm/V, 0.059%, 0.36 for 5BZ/3BLT/92NKN; and 181pC/N, 190pm/V, 0.061%, 0.39 for 6BZ/2BLT/92NKN. It is found that the electromechanical coupling coefficient has a better temperature stability than the piezoelectric coefficient in the studied system due to a large temperature-dependent compliance change. The results demonstrate that engineering an MPB is highly effective in tailoring temperature stability of piezoceramics.},
author = {Wang, Ruiping and Wang, Ke and Yao, Fangzhou and Li, Jing-Feng and Schader, Florian H. and Webber, Kyle Grant and Jo, Wook and Roedel, Juergen},
doi = {10.1111/jace.13604},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {2177-2182},
peerreviewed = {Yes},
title = {{Temperature} {Stability} of {Lead}-{Free} {Niobate} {Piezoceramics} with {Engineered} {Morphotropic} {Phase} {Boundary}},
volume = {98},
year = {2015}
}
@article{faucris.110334224,
abstract = {
Measurement and calculation of anhysteretic curves is a well-established method in the field of magnetic materials and is applied to ferroelectric materials here. The anhysteretic curve is linked to a stable equilibrium state in the domain structure, and ignores dissipative effects related to mechanisms such as domain wall pinning. In this study, an experimental method for characterising the anhysteretic behaviour of ferroelectrics is presented, which is subsequently used to determine the anhysteretic polarisation response of polycrystalline barium titanate and a doped lead zirconate titanate composition at room temperature. Various external parameters, such as electric field, stress, and temperature, can significantly affect ferroelectric behaviour. Ferroelectric hysteresis curves can assess the importance of such effects but cannot distinguish their contribution on the different intrinsic and extrinsic mechanisms involved in ferroelectric behaviour. In this work, the influence of compressive stress on the anhysteretic polarisation is measured and discussed.The comparison of the polarization loop to the anhysteretic curve under compressive stress elucidates the effects on the stable equilibrium domain configuration and dynamic effects associated to dissipation.
},
author = {Kaeswurm, Barbara and Daniel, Laurent and Webber, Kyle Grant},
doi = {10.1088/1361-6463/aaa698},
faupublication = {yes},
journal = {Journal of Physics D: Applied Physics},
peerreviewed = {Yes},
title = {{The} {Anhysteretic} {Polarisation} of {Ferroelectrics}},
volume = {51},
year = {2018}
}
@article{faucris.111513204,
abstract = {A comprehensive review on the latest development of the antiferroelectric <-> ferroelectric phase transition is presented. The abrupt volume expansion and sudden development of polarization at the phase transition has been extensively investigated in PbZrO3-based perovskite ceramics. New research developments in these compositions, including the incommensurate domain structure, the auxetic behavior under electric fields in the induced ferroelectric phase, the ferroelastic behavior of the multicell cubic phase, the impact of radial compression, the unexpected electric field-induced ferroelectric-to-antiferroelectric transition, and the phase transition mechanical toughening effect have been summarized. Due to their significance to lead-free piezoelectric ceramics, compounds with antiferroelectric phases, including NaNbO3, AgNbO3, and (Bi1/2Na1/2)TiO3, are also critically reviewed. Focus has been placed on the (Bi1/2Na1/2)TiO3BaTiO3 solid solution where the electric field-induced ferroelectric phase remains even after the applied field is removed at room temperature. Therefore, the electric field-induced antiferroelectric-to-ferroelectric phase transition is a key to the poling process to develop piezoelectricity in morphotropic phase boundary (MPB) compositions. The competing phase transition and domain switching processes in 0.93(Bi1/2Na1/2)TiO30.07BaTiO3 are directly imaged with nanometer resolution using the unique in situ transmission electron microscopy (TEM) technique.},
author = {Tan, Xiaoli and Ma, Cheng and Frederick, Joshua and Beckman, Sarah and Webber, Kyle Grant},
doi = {10.1111/j.1551-2916.2011.04917.x},
faupublication = {no},
journal = {Journal of the American Ceramic Society},
pages = {4091-4107},
peerreviewed = {Yes},
title = {{The} {Antiferroelectric} <-> {Ferroelectric} {Phase} {Transition} in {Lead}-{Containing} and {Lead}-{Free} {Perovskite} {Ceramics}},
volume = {94},
year = {2011}
}
@article{faucris.119456964,
abstract = {A time-dependent phase field model was utilized to investigate the electric field induced tetragonal-to-orthorhombic (T -> O) planar phase transformations of perovskite materials, indicated by the simulated semi-discontinuous polarization-electric field hysteresis. Simulations show that transformations are sensitive to the crystallographic orientation of the applied electric field, the energy threshold for 90 degrees domain switching and the rotation path between tetragonal variants. This indicates that the field induced phase transformation behavior has a significant influence on the evaluation and validation of the Landau coefficients. (C) 2011 American Institute of Physics. [doi:10.1063/1.3644957]},
author = {Franzbach, Daniel J. and Xu, Bai-Xiang and Mueller, Ralf and Webber, Kyle Grant},
doi = {10.1063/1.3644957},
faupublication = {no},
journal = {Applied Physics Letters},
keywords = {dielectric hysteresis;dielectric polarisation;electric domains;ferroelectric materials;ferroelectric switching;ferroelectric transitions;relaxor ferroelectrics},
peerreviewed = {Yes},
title = {{The} effects of polarization dynamics and domain switching energies on field induced phase transformations of perovskite ferroelectrics},
volume = {99},
year = {2011}
}
@article{faucris.243304130,
abstract = {The formation of associated defects (e.g.[AlTi-VO]˙) upon acceptor doping is commonly seen as a reason for trapping of mobile vacancies in perovskite ionic conductors and electromechanical hardening in piezoelectric perovskites. In order to clarify the presence of associated defects in Al-doped (Na1/2,Bi1/2)TiO3(NBT-Al) and Al-substituted ((Na,K)1/2Bi1/2)TiO3-BiAlO3(NKBT-BA), we employ a combination of impedance spectroscopy,27Al NMR spectroscopy, and electronic structure calculations. Our results indicate that associated defects between and oxygen vacancies can only be found in case of low acceptor doping concentrations. This suggests a decreased driving force for defect association at high doping concentrations as the reason for the non-linear dependence between acceptor concentration and oxygen ionic conductivity for NBT-based ceramics. Furthermore, the combination of experimental and theoretical techniques provides clear evidence for the successive occupation of the B-site, the A-site, and finally the formation of a secondary phase with increasing Al3+content. Altogether, these results call for a new evaluation of the interaction between aliovalent dopants and O2−vacancies in acceptor-doped functional oxides, with implications for the design of ionic conductors as well as ferroelectric materials.},
author = {Groszewicz, Pedro B. and Koch, Leonie and Steiner, Sebastian and Ayrikyan, Azatuhi and Webber, Kyle Grant and Frömling, Till and Albe, Karsten and Buntkowsky, Gerd},
doi = {10.1039/d0ta03554h},
faupublication = {yes},
journal = {Journal of Materials Chemistry A},
note = {CRIS-Team Scopus Importer:2020-10-02},
pages = {18188-18197},
peerreviewed = {Yes},
title = {{The} fate of aluminium in ({Na},{Bi}){TiO3}-based ionic conductors},
volume = {8},
year = {2020}
}
@article{faucris.123154504,
abstract = {In this study, the time-dependent electromechanical response of lead-free piezoceramic 0.93(Na1/2Bi1/2) TiO3-0.07BaTiO(3) to the applied electrical field was investigated. Large creep behavior was observed in both the polarization and the strain response, which can be attributed to the transition from a nonergodic relaxor to a state with a long-range ferroelectric order. This transition under a constant electric loading is a gradual process with a cascade behavior, observed under electric fields ranging from 1.2 to 1.6 kV/mm. The critical electric field to trigger this cascade effect was found to be approximately 1.15 kV/mm. This phenomenon indicates that the electric fieldinduced state transition is similar to a "self-catalyzed" behavior that depends on both the magnitude of electric loading and the holding time. Following the creep experiment, the electromechanical behavior was characterized to determine the completeness of the relaxor-ferroelectric transition. Published by AIP Publishing.},
author = {Chen, D. and Ayrikyan, Azatuhi and Webber, Kyle Grant and Kamlah, M.},
doi = {10.1063/1.4978704},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Time}-dependent electromechanical response of 0.93({Na1}/{2Bi1}/2) {TiO3}-0.{07BaTiO}(3) lead-free piezoceramic under constant electric field},
volume = {121},
year = {2017}
}
@article{faucris.119467964,
abstract = {After twenty years of partly quiet and ten years of partly enthusiastic research into lead-free piezoceramics there are now clear prospects for transfer into applications in some areas. This mimics prior research into eliminating lead from other technologies that resulted in restricted lead use in batteries and dwindling use in other applications. A figure of merit analysis for key devices is presented and used to contrast lead-containing and lead-free piezoceramics. A number of existing applications emerge, where the usage of lead-free piezoceramics may be envisaged in the near future. A sufficient transition period to ensure reliability, however, is required. The use of lead-free piezoceramics for demanding applications with high reliability, displacements and frequency as well as a wide temperature range appears to remain in the distant future. New devices are outlined, where the figure of merit suggests skipping lead-containing piezoceramics altogether. Suggestions for the next pertinent research requirements are provided. (C) 2014 Elsevier Ltd. All rights reserved.},
author = {Rödel, Jürgen and Webber, Kyle Grant and Dittmer, Robert and Jo, Wook and Kimura, Masahiko and Damjanovic, Dragan},
doi = {10.1016/j.jeurceramsoc.2014.12.013},
faupublication = {no},
journal = {Journal of the European Ceramic Society},
keywords = {Lead-free ferroelectrics;Piezoelectrics;Piezoelectric transducer;Piezoelectric actuator;Ferroelectricity},
pages = {1659-1681},
peerreviewed = {Yes},
title = {{Transferring} lead-free piezoelectric ceramics into application},
volume = {35},
year = {2015}
}
@article{faucris.111484164,
abstract = {Due to a larger specific volume of the ferroelectric phase, the antiferroelectric-to-ferroelectric transition is believed to have an enhanced toughening effect against fracture. The toughening requires a non-recoverable transformation in the crack process zone. Complementary measurement of the crystal symmetry, dielectric constant, field-induced polarization and Raman spectrum on ceramic Pb0.99Nb0.02[(Zr0.57Sn0.43)(0.92)Ti-0.08](0.98)O-3 indicates that the antiferroelectric and the ferroelectric states are equally stable at room temperature. Raman mapping further reveals the presence of the ferroelectric phase in a localized zone at the crack tip after unloading. A significant phase-transition-toughening effect is demonstrated in the antiferroelectric ceramic with both indentation fracture and R-curve experiments. The effect in this model composition leads to toughness values similar to 50% larger than other antiferroelectric ceramics with similar compositions and 60-130% higher than ferroelectric Pb(Zr,Ti)O-3 ceramics. A simple analysis confirms the toughening effect from both volumetric phase transition and deviatoric domain switching during the transformation. The results suggest that other materials near phase boundaries may have similar high fracture resistance. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.},
author = {Tan, Xiaoli and Young, S.E. and Seo, Yo-Han and Zhang, J.Y. and Hong, W and Webber, Kyle Grant},
doi = {10.1016/j.actamat.2013.09.038},
faupublication = {no},
journal = {Acta Materialia},
keywords = {Antiferroelectric ceramics;Phase transition toughening;Raman mapping;R-curve},
month = {Jan},
pages = {114-121},
peerreviewed = {Yes},
title = {{Transformation} toughening in an antiferroelectric ceramic},
volume = {62},
year = {2014}
}
@article{faucris.112221824,
author = {Khansur, Neamul Hayet and Glaum, Julia and Clemens, Oliver and Zhang, Hailong and Daniels, John E. and Webber, Kyle Grant},
doi = {10.1016/j.ceramint.2017.04.055},
faupublication = {yes},
journal = {Ceramics International},
keywords = {C. Mechanical properties; C. Piezoelectric properties; D. Perovskite; E. Functional applications},
pages = {9092-9098},
peerreviewed = {Yes},
title = {{Uniaxial} compressive stress and temperature dependent mechanical behavior of (1-x){BiFeO3}-{xBaTiO3} lead-free piezoelectric ceramics},
volume = {43},
year = {2017}
}
@article{faucris.271393752,
abstract = {Multiferroics have received considerable interest over the last decade due to the fascinating fundamental phenomena and potential use in various applications, such as low-power electronics and spintronics. Among those, investigations have focused on the coexistence of ferroelectric and ferromagnetic mate-rials. Here, we report the rare case that the para-to ferroelastic ordering transition in antiferromagnet Mn2V2O7 occurred at T-S = 260-280 K, verified by temperature-dependent magnetization measurements, dielectric, differential scanning calorimetry, and macroscopic strain-stress hysteresis loops. Furthermore, this transition was accompanied by a structural transition from the high-temperature C2/m monoclinic phase (beta-phase) to a low-temperature P (1) over bar triclinic phase (alpha-phase), as identified by temperature-dependent X-ray diffraction. Consequently, T-S can be successfully increased by Co-and Ni-doping and decreased by Ca-doping. Thus, the phase diagram was established for the structural stability of (Mn(1-x)A(x))(2)V2O7 (A = Co, Ni, and Ca). In addition, the physical and chemical pressure effects were applied on (Mn(1-x)C(a)x)(2)V2O7 to correlate the ferroelastic (TS) and antiferromagnetic (TN) orderings. Consequently, the magnetoelastic coupling was revealed, and a unique multiferroic material (Mn2V2O7) with a fer-roelastic and antiferromagnetic ordering was obtained. (C) 2022 Elsevier Ltd. All rights reserved.},
author = {Chen, H. J. and Yeh, C. H. and Kuo, T. W. and Kakarla, D. Chandrasekhar and Wu, H. C. and Yen, T. W. and Huang, S. M. and Chou, H. and Chou, M. C. and Chen, H. W. and Kuo, S. W. and Chuang, Y. C. and Chang, C. K. and Eckstein, Udo and Khansur, Neamul Hayet and Webber, Kyle Grant and Yang, H. D.},
doi = {10.1016/j.mtphys.2022.100623},
faupublication = {yes},
journal = {Materials Today Physics},
note = {CRIS-Team WoS Importer:2022-03-25},
peerreviewed = {Yes},
title = {{Unique} multiferroics with tunable ferroelastic transition in antiferromagnet {Mn2V2O7}},
volume = {23},
year = {2022}
}