Currents induce magnetization torques via spin-transfer when the spin angular momentum is conserved or via relativistic spin-orbit coupling. Beyond simple models, the relationship between material properties and spin-orbit torques is not known. Here, we present a novel phenomenology of current-induced torques that is valid for any strength of intrinsic spin-orbit coupling. In ${\mathrm{Pt}\left|\mathrm{Co}\right|\mathrm{AlO}}_x$, we demonstrate that the domain walls move in response to a novel relativistic dissipative torque that is dependent on the domain wall structure and that can be controlled via the Dzyaloshinskii-Moriya interaction. Unlike the nonrelativistic spin-transfer torque, the new torque can, together with the spin-Hall effect in the Pt layer, move domain walls by means of electric currents parallel to the walls.

• Received 1 July 2013

DOI:https://doi.org/10.1103/PhysRevB.88.085423