Anisotropic gradient driven domain wall motion in antiferromagnets.

Searching for new energy-saving method of controlling antiferromagnetic (AFM) domain wall is one of the most important issues for AFM spintronic device design. In this work, we study theoretically and numerically the domain wall motion in AFM nanowires driven by electric voltage induced anisotropy gradient. The domain wall velocity depending on the gradient and intrinsic material properties are simulated based on the Landau-Lifshitz-Gilbert equation and also deduced using the energy dissipation theorem. The domain wall moves at a nearly constant velocity for small gradients, while accelerates for large gradients due to the enlargement of the domain wall width during the motion. Furthermore, the calculated results are confirmed to be independent of the lattice dimension. Comparing with those electric current driven methods, the anisotropy gradient driven domain wall motion through tuning electric voltage on particular heterostructures is expected to be more energy saving. Thus, our work unveils a promising method of controlling AFM domain walls, and does provide useful information for future AFM spintronic applications.