Field-free switching of magnetization induced by spin–orbit torque in Pt/CoGd/Pt thin film

Abstract

All-electric control of magnetism is essential for the future ultralow-power memory and logic spintronic applications. Here, we report a highly efficient way to realize field-free current-induced switching of magnetization in ferrimagnetic CoGd, which is deposited with composite target. The critical switching current density is as low as ∼1 × 107 A/cm2. Without any gradient designs, our CoGd film intrinsically exhibits extraordinary titled magnetic anisotropy and bias-fields. The field-free switching of magnetizations can be achieved by applying current pulses in x or y directions. We further establish a coupled ferrimagnetic macrospin model subjected to the Landau–Lifshitz–Gilbert–Slonczewski equation, and the theoretical results agree with experiments well. All these results suggest that deposition with composite target is the optimal route to fabricate a high performance spin–orbit torque device, which provides multiple routes to achieve field-free, deterministic, and low-consumption magnetization switching.