Spin–orbit torque induced magnetization switching for an ultrathin MnGa/Co2MnSi bilayer

We investigated spin–orbit torque (SOT) induced magnetization switching and SOT efficiency for Mn1.8Ga1.0 (MnGa) single layers and MnGa/Co2MnSi (CMS) bilayers. Magnetization measurements showed that ultrathin MnGa and CMS were antiferromagnetically coupled to each other with clear perpendicular magnetization. SOT-induced magnetization switching was observed for both MnGa/CMS/Ta and MnGa/Ta stacks, and the switching current was reduced by a half in the MnGa/CMS/Ta stack. Examination of SOT acting on the domain walls revealed that the effective magnetic field originating from the SOT was approximately five times stronger in the MnGa/CMS/Ta stack than in the MnGa/Ta stack. These results indicate that the MnGa/CMS bilayer structure is effective in enhancing the efficiency of SOT generation.