The role of Ca/Zr ratio on the local structure and phase transitions in lead-free (Ba,Ca)(Zr,Ti)O3

Dobesh D, Gadelmawla A, Miyazaki H, Hinterstein M, Kimura K, Maier J, Banerjee S, Zeair O, Mehta S, da Silva LL, Khansur NH, Hayashi K, de Ligny D, Webber KG, Cicconi MR (2024)

Publication Type: Journal article

Publication year: 2024

Journal

DOI: 10.1016/j.jeurceramsoc.2024.03.003

Abstract

In this study, the structural phase transitions are investigated as a function of composition and temperature for polycrystalline x(Ba0.7Ca0.3)TiO3-(1 − x)Ba(Zr0.2Ti0.8)O3 (x = 0.40, 0.45, 0.50, 0.55, and 0.60) through a combination of Raman spectroscopy, synchrotron X-ray diffraction, and dielectric spectroscopy. The aim is to gain insight into the complex phase boundary region responsible for the excellent electromechanical properties. The results demonstrate the correlation between local site substitutions based on the stoichiometric variations to the microstructure and dielectric properties. The dielectric response has been correlated with the BCT/BZT content displaying a maximum depending on the phase content. Additionally, in situ temperature-dependent Raman, permittivity, and pair distribution function (PDF) studies were performed from −60 °C to 130 °C to highlight the structure and phase evolution. In particular, the in situ temperature-dependent Raman measurements reveal sudden discontinuities in the vibrational modes that correspond to the structural changes in the perovskite structure. Therefore, the results of the permittivity response, based on the average of a large volume, are consistent with the local structural changes obtained by other techniques. Indeed, correlations of Raman, X-ray diffraction, and PDFs obtained from synchrotron X-ray total scattering data, along with permittivity measurements allowed the identification of the discrete ferro- to paraelectric phase transitions and a more robust characterization. The rotation and distortion of the octahedral caused by oxygen displacement are driving forces behind symmetry changes and phase transitions, explaining the mechanism of polymorphic phase transition based on A- and B-site substitution. Therefore, this work provides a comprehensive understanding of temperature and composition-dependent phase transitions in BCZT.

Authors with CRIS profile

Additional Organisation(s)

Involved external institutions

Nagoya Institute of Technology / 名古屋工業大学 Nagoya Kōgyō Daigaku Japan (JP) Karlsruhe Institute of Technology (KIT) Germany (DE)

How to cite

APA:

Dobesh, D., Gadelmawla, A., Miyazaki, H., Hinterstein, M., Kimura, K., Maier, J.,... Cicconi, M.R. (2024). The role of Ca/Zr ratio on the local structure and phase transitions in lead-free (Ba,Ca)(Zr,Ti)O3. Journal of the European Ceramic Society. https://doi.org/10.1016/j.jeurceramsoc.2024.03.003

MLA:

Dobesh, David, et al. "The role of Ca/Zr ratio on the local structure and phase transitions in lead-free (Ba,Ca)(Zr,Ti)O3." Journal of the European Ceramic Society (2024).

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