Fast Magnetization Switching by Linear Vertical Microwave-Assisted Spin-Transfer Torque

Abstract

The effect of vertical microwave magnetic field on spin-transfer torque switching in elliptical magnetic spin valve has been investigated by performing micromagnetic simulations including a spin-transfer torque term. The speed of magnetization switching can be accelerated by applying a vertical microwave magnetic field. Magnetization switching time decreases with the increase of the amplitude of vertical microwave magnetic field for both the fixed microwave frequency and current density. When the frequency of the microwave magnetic field coincides with the natural ferromagnetic resonance frequency of the elliptical spin valve, magnetization switching time is reduced to the minimum. Magnetization switching time can be reduced from 9.44 to 2.4 ns due to an effect of vertical microwave magnetic field. In addition, critical current density of magnetization reversal is strongly lowered in the presence of vertical microwave magnetic field.