Magnetic anisotropy by Rashba spin-orbit coupling in antiferromagnetic thin films

TL;DR

This paper investigates how Rashba spin-orbit coupling influences magnetic anisotropy in antiferromagnetic thin films, revealing different anisotropy behaviors depending on the symmetry breaking model, with implications for electrical control of magnetic states.

Contribution

It introduces models showing how inversion symmetry breaking affects magnetic anisotropy in antiferromagnets, highlighting the role of Rashba spin-orbit coupling.

Findings

Global ISB leads to easy-plane anisotropy

Local ISB results in perpendicular magnetic anisotropy

MAE influences Neel vector orientation and control

Abstract

Magnetic anisotropy in an antiferromagnet (AFM) with inversion symmetry breaking (ISB) is investigated. The magnetic anisotropy energy (MAE) resulting from the Rashba spin-orbit and s-d type exchange interactions is determined for two different models of AFMs. The global ISB model, representing the effect of a surface, an interface, or a gating electric field, results in an easy-plane magnetic anisotropy. In contrast, for a local ISB model, i.e., for a noncentrosymmetric AFM, perpendicular magnetic anisotropy (PMA) arises. Both results differ from the ferromagnetic case, in which the result for PMA depends on the band structure and dimensionality. These MAE contributions play a key role in determining the direction of the Neel order parameter in antiferromagnetic nanostructures, and reflect the possibility of electrical-field control of the Neel vector.