Efficient spin-orbit-torque magnetization switching in a spin-orbit ferromagnetic-semiconductor (Ga,Mn)As single layer

Spin-orbit torque (SOT) magnetization switching is an efficient method to control magnetization. In SOT switching, controlling a field-like torque strength is indispensable to reduce the critical current density; however, this is difficult because the field-like torque is intrinsic to the material system used. Here, we show that it can be suppressed in a spin-orbit ferromagnet single layer of (Ga,Mn)As by a current-induced Oersted field due to its strong Dresselhaus spin-orbit coupling and non-uniform current distribution. We obtained an extremely low switching current density of 4.6×10^4 A/cm^2, three orders of magnitude smaller than that observed in typical metal bilayers.