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 the magnetic tunnel junctions of CoFeB free layer having in-plane magnetization. It is found that the critical switching current depends on the feature of switching modes as well as the junction geometries. Especially, the long pulse mode switching generates the equilibrium remnant magnetization states before complete magnetization reversal. It results a robust switching by reducing the local magnetization anomalies. The current driven switching is understood by the combined effect of spin transfer and thermal activation.