Control of spins in a nano-sized magnet using electric-current.

With the development of spintronics, spin-transfer torque control of magnetic properties receives considerable attention. In this paper the Landau–Lifshitz–Gilbert equation including the torque term is used to investigate the magnetic moment dynamics in the free layer of the ferromagnet/non-magnetic/ferromagnet (FM1/N/FM2) structures. It is found that the reverse critical time decreases with the current increasing. The critical time as a function of current for the perpendicular and parallel easy magnetic axes are the same. The critical time increases with the damping factor increasing. In the case of large current the influence of the damping factor is smaller, but in the case of little torque the critical time increases greatly with the damping increasing. The direction of the magnetization in the fixed layer influences the critical time, when the angle between the magnetization and the direction changes from 0.1 to 0.4, the critical time decreases from 26.7 to 15.6. [ABSTRACT FROM AUTHOR]