Stable magnetization states under a spin-polarized current and a magnetic field

Abstract

Stable magnetization states of a nanoscale magnet under torque by a spin-polarized current and one under torque by an external magnetic field are studied theoretically. We consider six configurations for the combination of the three directions, that is, the easy axis of the magnet, the spin polarization of the current, and the magnetic field. For each configuration, all the possible stable magnetization states are revealed by constructing a phase diagram in the current-field plane on the basis of the Landau-Lifshitz-Gilbert equation. In addition, analyses on the dynamic behaviors of the magnetization are presented. We find that our system does not exhibit any chaotic behaviors. Nevertheless, the initial condition has a significant effect on the magnetization motion.