Magnetic anisotropy due to Rashba interaction in antiferromagnets

Ieda, Junichi   ; Barnes, S. E.*; Maekawa, Sadamichi

Magnetic anisotropy of an antiferromagnet (AFM) with the inversion symmetry breaking (ISB) is theoretically investigated. The magnetic anisotropy energy (MAE) resulting from the Rashba spin-orbit (RSO) and s-d type exchange interactions is determined for tight binding models of AFMs. We introduce two types of the Rashba interactions: The global ISB model, representing the effect of a surface, 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, a perpendicular magnetic anisotropy (PMA) arises. These MAE contributions have a key role in determining the direction of the Neel order parameter in AFM nanostructures and reflect the possibility of electrical-field control of the Neel vector.