Switching of Perpendicular Magnetization via ac Spin-Orbit Torque

Current-induced magnetization switching by spin-orbit torques has become of technological interest for spintronics, because it provides high-speed operation while preserving device stability. However, conventional spin-orbit-torque switching requires a rather large switching current, and an external in-plane magnetic field for deterministic switching. In this study an alternative switching scheme using a circularly polarized alternating current is investigated, which allows not only a low switching current, but also field-free switching. This achievement provides a useful means to realize energy-efficient spin-orbit-torque devices.