Higher-order magnetic anisotropy in soft-hard magnetic materials

Abstract

We have computationally studied the properties of higher-order magnetic anisotropy constants in an L10/A1-FePt core-shell system which is characterized by a strong second-order two-ion Fe-Pt anisotropy component. We show that the core-shell structure induces an unexpected fourth-order anisotropy constant K2, the magnitude of which varies nonmonotonically with the core-size ratio R reaching a peak at R≈0.50. Furthermore, we find that K2 scales with the normalized magnetization by (M/Ms)2.2 at temperatures below the Curie temperature, a remarkable deviation from the established Callen-Callen theory which instead predicts a scaling exponent of 10. We construct an analytic model which demonstrates K2 arises from the canting of the core and shell magnetization, and successfully reproduces and justifies the scaling exponent obtained from numerical simulation.

Metadata

Item Type:	Article
Authors/Creators:	Binh, Nguyen Thanh Jenkins, Sarah (sj681@york.ac.uk) Ruta, Sergiu (sir503@york.ac.uk) Evans, Richard F.L. https://orcid.org/0000-0002-2378-8203 Chantrell, Roy W. https://orcid.org/0000-0001-5410-5615
Copyright, Publisher and Additional Information:	Funding Information: The authors would like to thank Daniel Meilak for assistance with optimizing the simulated core-shell system. The financial support of the Advanced Storage Research Consortium (ASRC) is gratefully acknowledged. S.R. acknowledges funding from the EPSRC TERASWITCH project (project ID EP/T027916/1). S.J. acknowledges funding by the German Research Foundation (DFG) project No. 320163632. We are also grateful for computational support from the University of York High Performance Computing service, Viking, and the Research Computing team. Publisher Copyright: © 2023 American Physical Society. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details
Dates:	Accepted: 22 December 2022 Published: 27 January 2023
Institution:	The University of York
Academic Units:	The University of York > Faculty of Sciences (York) > Physics (York)
Depositing User:	Pure (York)
Date Deposited:	22 Jun 2023 09:00
Last Modified:	10 Apr 2025 23:35
Published Version:	https://doi.org/10.48550/arXiv.2210.07875
Status:	Published
Refereed:	Yes
Identification Number:	10.48550/arXiv.2210.07875
Related URLs:	http://www.scopus.com/inward/record.url?...
Open Archives Initiative ID (OAI ID):	oai:eprints.whiterose.ac.uk:200695

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Higher-order magnetic anisotropy in soft-hard magnetic materials

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