Temperature dependent magnetic anisotropy in metallic magnets from an ab-initio electronic structure theory: L1_0-ordered FePt

TL;DR

This paper presents a first-principles electronic structure theory to study how magnetic anisotropy varies with magnetization in metallic ferromagnets, specifically applied to L1_0-ordered FePt, showing good agreement with experiments.

Contribution

The paper introduces a relativistic ab-initio method to analyze temperature-dependent magnetic anisotropy in metallic magnets, applied to FePt.

Findings

Magnetic anisotropy K remains perpendicular to Fe/Pt layers across all magnetizations.

K is proportional to M^2 over a broad M range.

Easy axis determined near the Curie temperature aligns with experimental observations.

Abstract

On the basis of a first-principles, relativistic electronic structure theory of finite temperature metallic magnetism, we investigate the variation of magnetic anisotropy, K, with magnetisation, M, in metallic ferromagnets. We apply the theory to the high magnetic anisotropy material, L1_0-ordered FePt, and find its uniaxial K consistent with a magnetic easy axis perpendicular to the Fe/Pt layering for all M and to be proportional to M^2 for a broad range of values of M. For small M, near the Curie temperature, the calculations pick out the easy axis for the onset of magnetic order. Our results are in good agreement with recent experimental measurements on this important magnetic material.