The rise of spin-flip transitions in the anomalous Hall effect of FePt alloy

TL;DR

This study uses first-principles calculations to reveal that spin-flip transitions significantly influence the anomalous Hall conductivity in FePt alloys, driven by strong spin-orbit coupling and contributing to anisotropic effects.

Contribution

It demonstrates the crucial role of spin-flip transitions in the anomalous Hall effect of FePt, highlighting their origin and impact on anisotropy and disorder effects.

Findings

Spin-flip transitions are key to FePt's anomalous Hall conductivity.

Large spin-orbit coupling in Pt enhances spin-flip transitions.

Disorder influences the anisotropy of the Hall effect.

Abstract

We carry out first-principles calculations which demonstrate the importance of spin-flip transitions for the intrinsic anomalous Hall conductivity of ordered FePt alloys. We show the such transitions get enhanced by large spin-orbit coupling of Pt atoms, becoming negligible when Pt is replaced by lighter isoelectronic Pd. We find that spin-flip transitions in FePt originate not only from conventional band anticrossings at the Fermi level, but also from transitions between well-separated pairs of bands with similar dispersions. We also predict a strong anisotropy in the anomalous Hall conductivity of FePt, which comes from spin-flip transitions entirely, and investigate the influence of disorder on it.