Lattice-compliant simulations of antiferromagnetic textures and their response to spin-orbit torques

Abstract

Spin textures in perfectly ordered antiferromagnetic ultrathin films are evaluated on the basis of atomistic simulations and compared to the results of recent extensions of the ($\mathbf{l},\mathbf{m}$) decomposition model. A comparison between similar textures supported by either a bcc or a fcc lattice shows that the sole inclusion of symmetric Heisenberg exchange interactions suffices to provide, when geometry commands, a natural canting between neighboring ${\mathbf{s}}_{\ensuremath{\uparrow}}$ and ${\mathbf{s}}_{\ensuremath{\downarrow}}$ spins within a texture. Moreover, a pure ``at lattice points'' dipole model leads to natural symmetries, in clear disagreement with expectations from the ($\mathbf{l},\mathbf{m}$) model. Inversely, properties such as wall mobility under spin-orbit torques depending mostly on wall geometrical characteristics such as chirality and chirality axis orientation prove, as anticipated, primarily lattice immune.