Stability analysis of current-driven domain wall in the presence of spin Hall effect

We investigate theoretically the current-driven domain wall dynamics in heavy-metal-ferromagnet bilayers. Within Lagrangian formalism, the influence of spin Hall effect on the behavior and stability of Walker's profile is analyzed. We find that in the high-current regime, although the spin Hall current alters the wall mobility slightly, the Walker breakdown is removed. In the low-current regime, the spin Hall effect makes the wall motion dependant on the polarity. The static Neel wall can be transformed into Bloch one and the polarity of Bloch wall can be switched. Especially, for proper initial polarity and current, the wall propagates along the current direction. (C) 2013 AIP Publishing LLC.