Authors:	Masciocchi, Giovanni Fattouhi, Mouad Kehlberger, Andreas Lopez-Diaz, Luis Syskaki, Maria-Andromachi Kläui, Mathias
Title:	Strain-controlled domain wall injection into nanowires for sensor applications
Online publication date:	4-Feb-2022
Year of first publication:	2021
Language:	english
Abstract:	We investigate experimentally the effects of strain on the injection of 180 & DEG; 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, Co 40 Fe 40 B 20, Ni, and Ni 82 Fe 18 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.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-6736
Version:	Accepted version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	In Copyright
Information on rights of use:	http://rightsstatements.org/vocab/InC/1.0/
Journal:	Journal of applied physics 130
Pages or article number:	183903
Publisher:	American Inst. of Physics
Publisher place:	Melville, NY
Issue date:	2021
ISSN:	0021-8979
Publisher URL:	https://doi.org/10.1063/5.0069661
Publisher DOI:	10.1063/5.0069661
Appears in collections:	JGU-Publikationen