Investigation of spin-orbit torque switching mechanism in crystalline ferromagnetic semiconductor

We investigated the spin-orbit torque (SOT) switching mechanism of a single layer of crystalline diluted ferromagnetic semiconductor by simulating the current scan hysteresis using the Landau-Lifshitz-Gilbert equation. Our study focuses on the switching of the out-of-plane magnetization component during current scans to provide a detailed understanding of the SOT switching process. The simulation results reveal that the SOT switching strongly depends on the relative strengths of the damping-like torque (DLT) and field-like torque (FLT). Through a systematic analysis, we found that the DLT to FLT ratio required for full SOT switching of the out-of-plane magnetized (GaMn) (AsP) film falls within the range of 0.5-1.0. We also identified a relationship between the DLT to FLT ratio and the linear behavior of the out-of-plane component of magnetization during current scans under a strong in-plane bias field. This suggests that the DLT to FLT ratio of a ferromagnetic film can be directly determined from current scan measurements under a large external field, providing crucial information for developing SOT-based devices.