Field-Free Spin-Orbit Torque Driven Switching of Perpendicular Magnetic Tunnel Junction through Bending Current

Abstract

Current-induced spin-orbit torques (SOTs) enablefast andefficient manipulation of the magnetic state of magnetic tunnel junctions(MTJs), making them attractive for memory, in-memory computing, andlogic applications. However, the requirement of the external magneticfield to achieve deterministic switching in perpendicularly magnetizedSOT-MTJs limits its implementation for practical applications. Here,we introduce a field-free switching (FFS) solution for the SOT-MTJdevice by shaping the SOT channel to create a "bend"in the SOT current. The resulting bend in the charge current createsa spatially nonuniform spin current, which translates into inhomogeneousSOT on an adjacent magnetic free layer enabling deterministic switching.We demonstrate FFS experimentally on scaled SOT-MTJs at nanosecondtime scales. This proposed scheme is scalable, material-agnostic,and readily compatible with wafer-scale manufacturing, thus creatinga pathway for developing purely current-driven SOT systems.