Effects of composition and chemical disorder on the magnetocrystalline anisotropy of Fe_{x}Pt_{1-x} alloys

TL;DR

This study uses first principles calculations to analyze how composition and chemical disorder affect the magnetocrystalline anisotropy energy in FePt alloys, aligning with experimental findings and highlighting the importance of Fe layer completeness.

Contribution

It provides a detailed theoretical analysis of the impact of chemical disorder and composition on MAE in FePt alloys, extending experimental insights with site- and species-resolved contributions.

Findings

Fe-rich samples have larger MAE under chemical disorder

MAE depends on the completeness of Fe layers

Theoretical results agree with experimental observations

Abstract

We perform first principles calculations of the magnetocrystalline anisotropy energy (MAE) of the L1_{0}-like Fe_{x}Pt_{1-x} samples studied experimentally by Barmak and co-workers in [J. Appl. Phys. 98 (2005) 033904]. The variation of composition and long-range chemical order in the samples was studied in terms of the coherent potential approximation. In accordance with experimental observations, we find that, in the presence of long-range chemical disorder, Fe-rich samples exhibit a larger MAE than stoichiometric FePt. By considering the site- and species-resolved contributions to the MAE, we infer that the MAE is primarily a function of the degree of completeness of the nominal Fe layers in the L1_{0} FePt structure.