Antiferromagnetic domain walls under spin-orbit torque

Abstract: Domain walls in antiferromagnets under a spin-polarized current present rich dynamics that is not observed in ferromagnets, and it is tunable by the current polarization. Precessional dynamics is obtained for perpendicular spin polarization, in agreement with expectations in older works. Propagating walls are obtained for an in-plane polarization. We obtain the velocity as a function of current by a perturbation method for low velocities, and the wall profile is found to lack a definite parity. For high velocities, the main features of the wall profile are obtained by a direct solution of an equation that is valid in a limiting case. We discuss the magnetization of the dynamical walls and find that this can become large, providing a potential method for observations. Oscillatory motion of domain walls is obtained for spin polarization that has both perpendicular and in-plane components, and an analytical description is given.