Field-free magnetization switching driven by interfacial spin-orbit torque at an all-oxide interface

Spin-orbit torque (SOT)-driven magnetization switching has the potential to enable ultrafast operation and low power consumption in memory and logic technologies. SOT devices generally involve metal-based heterostructures, but oxide materials are competitive, offering highly tunable electronic properties including interfacial spin–orbit coupling (SOC) and the Rashba–Edelstein effect. In this work, we demonstrate field-free magnetization switching enabled by enhanced interfacial SOC at a quasi two-dimensional (quasi-2D) electron gas interface between La 1-x Ca x MnO 3 and SrTiO 3 (STO). The quasi-2D interface is generated by engineering oxygen vacancies at the STO surface, which tune the interfacial SOC. The SOC-driven magnetization switching shows a strong polarity-dependence on magnetic field —i.e., the magnetization switching is coherently clockwise or anticlockwise, depending on the direction of the magnetic field (applied above the coercive field). These findings demonstrate that quasi-2D electron gases in oxide materials systems are tunable platforms for the development of SOT memory and logic.