Dynamics of domain-wall motion driven by spin-orbit torque in antiferromagnets

The excitation of ultrafast dynamics in antiferromagnetic materials is an appealing feature for the realization of spintronic devices. Several experiments have shown that static and dynamic behaviors of the antiferromagnetic order are strictly related to the stabilization of multidomain states and the manipulation of their domain walls (DWs). Hence, a full micromagnetic framework should be used as a comprehensive theoretical tool for a quantitative understanding of those experimental findings. This model is used to perform numerical experiments to study the antiferromagnetic DW motion driven by the spin-orbit torque. We have derived simplified expressions for the DW width and velocity that exhibit a very good agreement with the numerical calculations in a wide range of parameters. Additionally, we have found that a mechanism limiting the maximum applicable current in an antiferromagnetic racetrack memory is the continuous domain nucleation from its edges, which is qualitatively different from what observed in the ferromagnetic case.