Dependence of Sub-Volume Excitation on Structural and Material Parameters in Precessional Regime of Spin Transfer Torque Magnetization Reversal

Abstract

We studied the structural and material parameter dependence of sub-volume excitation in a precessional regime of spin transfer torque (STT) magnetization reversal for CoFeB/MgO-based p-magnetic tunnel junctions (MTJs) using LLG micromagnetic simulation. The current density dependence of switching and incubation time in STT magnetization reversal can be globally scaled by the macrospin theory regardless of sub-volume excitation. The transit time has the minimum value at the minimum MTJ diameter where the sub-volume is excited. This critical diameter increases with an increase in exchange stiffness. The mechanism that sub-volume excitation is related to current density is also discussed.