Spin Drift Velocity, Polarization, and Current-Driven Domain-Wall Motion in (Ga,Mn)(As,P)

Abstract

Current-driven domain wall motion is studied in (Ga,Mn)(As,P) ferromagnetic semiconducting tracks with perpendicular anisotropy. A linear steady state flow regime is evidenced over a large temperature range of the ferromagnetic phase (0.1Tc < T < Tc). Close to 0 K, the domain wall velocity is found to coincide with the spin drift velocity. This result is obtained below the intrinsic threshold for domain wall motion which implies a non-adiabatic contribution to the spin transfer torque. The current spin polarization is deduced close to 0 K and to Tc. It suggests that the temperature dependence of the spin polarization can be inferred from the domain wall dynamics.