Magnetic anisotropy of FePt: effect of lattice distortion and chemical disorder

TL;DR

This study uses first principles calculations to analyze how lattice distortion and chemical disorder influence the magnetic anisotropy energy in FePt, highlighting chemical disorder as the dominant factor.

Contribution

The paper provides a detailed first-principles analysis of FePt's magnetic anisotropy, emphasizing the role of chemical disorder over lattice distortion, and reproduces experimental correlations.

Findings

Chemical disorder primarily determines MAE in FePt.

Lattice mismatch effects are less significant than chemical disorder.

Theoretical results align well with experimental data.

Abstract

We perform first principles calculations of the magnetocrystalline anisotropy energy in the five L10 FePt samples studied experimentally by Ding et al. [J. App. Phys. 97, 10H303 (2005)]. The effect of temperature-induced spin fluctuations is estimated by scaling the MAE down according to previous Langevin dynamics simulations. Including chemical disorder as given in experiment, the experimental correlation between MAE and lattice mismatch is qualitatively well reproduced. Moreover we determine the chemical order parameters that reproduce exactly the experimental MAE of each sample. We conclude that the MAE is determined by the chemical disorder rather than by lattice distortion.