Current-induced motion of a transverse magnetic domain wall in the presence of spin Hall effect

We theoretically study current-induced dynamics of a transverse magnetic domain wall in bi-layer nanowires consisting of a ferromagnetic layer on top of a nonmagnetic layer with strong spin-orbit coupling. Domain wall dynamics is characterized by two threshold current densities, J th WB and J th REV, where J th WB is a threshold for the chirality switching of the domain wall and J th REV is another threshold for the reversed domain wall motion caused by spin Hall effect. Domain walls with a certain chirality may move opposite to the electron-flow direction with high speed in the current range J th REV J J th WB for the system designed to satisfy the conditions J th WB > J th REV and α > β, where α is the Gilbert damping constant and β is the nonadiabaticity of spin torque. Micromagnetic simulations confirm the validity of analytical results.