Domain Wall Dynamics in Asymmetric Stacks: The Roles of Rashba Field and the Spin Hall Effect

The influence of spin-orbit torques, either Rashba and/or spin Hall effects, on the current-driven domain wall motion along high perpendicular magnetocrystalline anisotropy stacks, is analyzed by means of micromagnetic simulations and the one-dimensional model. The study indicates that the domain wall motion can be either in the direction of the current or opposing to it depending on the strength of the spin Hall effect in the presence of the Rashba spin-orbit torque, and therefore, it points out that both spin-orbit torques could be essential ingredients to describe recent experiments.