Current-driven switching property of MgO-based magnetic tunnel junctions with a CoFeB free layer with in-plane magnetization

Abstract

Spin-transfer torque enables magnetization switching by passing a spin-polarized current through nanostructures of spin valves or magnetic tunnel junctions. In this study, current-driven switching is investigated for magnetic tunnel junctions with a CoFeB free layer having in-plane magnetization. The critical switching current is found to depend on the feature of the switching modes and on the junction geometries. Especially, long-pulse mode switching generates equilibrium remnant magnetization states before complete magnetization reversal, which results in robust switching by reducing the local magnetization anomalies. The current-driven switching can be understood by using the combined effects of spin transfer and thermal activation.