Manipulation of Spin-Torque Generation Using Ultrathin Au

Controlling the generation of spin-orbit torque (SOT) with an electric field is important for spintronic applications in digital memory and magnetic sensors, but for the heavy metals typically used as SOT sources, insensitivity of bulk carrier density to an electric field makes generating torque difficult. This study demonstrates that creating SOT in an ultrathin film of gold can be managed effectively by ionic-liquid gating, which enables tuning of SOT-generation efficiency by a factor of two with a gate voltage of just \ifmmode\pm\else\textpm\fi{}1 V. The results offer an avenue to exploiting SOT efficiently in spintronic devices.