Current-driven domain wall motion with spin Hall effect: Reduction of threshold current density

We theoretically study the current-driven domain wall motion in the presence of both the spin Hall effect and an extrinsic pinning potential. The spin Hall effect mainly affects the damping ratio of the domain wall precession in the pinning potential. When the pinning potential is not too strong, this results in a significant reduction of a threshold current density for the depinning of a domain wall with certain polarity. We also propose one way to distinguish the spin Hall effect induced spin-transfer torque from the one induced by the Rashba spin-orbit coupling experimentally. (C) 2013 AIP Publishing LLC.