Interaction between spin–orbit torque and domain walls in a Ta/MnGa/NiAl structure

Abstract

We investigate the interaction between spin–orbit torque (SOT) and domain walls (DWs) created during magnetization reversal in perpendicularly magnetized ultrathin MnGa sandwiched between Ta and NiAl. We examine the out-of-plane hysteresis loops under various in-plane magnetic fields Hxs along the current I direction by using magnetotransport measurements. The applied I acts as an effective perpendicular magnetic field Heff on magnetization under Hx. The slope of Heff versus I varies proportionally to Hx and becomes saturated above ∼0.15 T, which is consistent with a model based on magnetization reversal through SOT-assisted chiral DW motion under Hx.