Strain-controlled domain wall injection into nanowires for sensor applications

Masciocchi G, Fattouhi M, Kehlberger A, Lopez-Diaz L, Syskaki MA, Klaeui M (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Journal of Applied Physics AIP Publishing

Book Volume: 130

Article Number: 183903

Journal Issue: 18

DOI: 10.1063/5.0069661

Abstract

We investigate experimentally the effects of strain on the injection of 180 ° domain walls (DWs) from a nucleation pad into magnetic nanowires, as typically used for DW-based sensors. In our study, the strain, generated by substrate bending, induces in the material a uniaxial anisotropy due to magnetoelastic coupling. To compare the strain effects, Co40 Fe40 B20, Ni, and Ni82 Fe18 samples with in-plane magnetization and different magnetoelastic coupling are deposited. In these samples, we measure the magnetic field required for the injection of a DW, by imaging using differential contrast in a magneto-optical Kerr microscope. We find that strain increases the DW injection field and that the switching mechanism depends strongly on the strain direction. We observe that low magnetic anisotropy facilitates the creation of a domain wall at the junction between the pad and the wire, whereas a strain-induced magnetic easy axis significantly increases the coercive field of the nucleation pad. Moreover, we find that these effects of strain-induced anisotropy can be counteracted by an additional magnetic uniaxial anisotropy perpendicular to the strain-induced easy axis. We perform micromagnetic simulations to support the interpretation of our experimental findings showing that the above described observations can be explained by the effective anisotropy in the device. The anisotropy influences the switching mechanism in the nucleation pad as well as the pinning of the DW at the wire entrance. As the DW injection is a key operation for sensor performances, the observations show that strain is imposing a lower limit for the sensor field operating window.

Involved external institutions

Sensitec GmbH DE Germany (DE) Johannes Gutenberg-Universität Mainz (JGU) DE Germany (DE) University of Salamanca / Universidad de Salamanca ES Spain (ES)

How to cite

APA:

Masciocchi, G., Fattouhi, M., Kehlberger, A., Lopez-Diaz, L., Syskaki, M.-A., & Klaeui, M. (2021). Strain-controlled domain wall injection into nanowires for sensor applications. Journal of Applied Physics, 130(18). https://doi.org/10.1063/5.0069661

MLA:

Masciocchi, Giovanni, et al. "Strain-controlled domain wall injection into nanowires for sensor applications." Journal of Applied Physics 130.18 (2021).

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