Magnetization Oscillations in a Ferromagnet/Nonmagnetic Metal/Ferromagnet Nanostructure under the Action of the Spin-Polarized Current

摘要

Oscillations of magnetization of a ferromagnetic disk included in the ferromagnetonmagnetic metal/ferromagnet nanostructure under the action of the spin-polarized current are studied in the macrospin approximation. Conditions for switching and oscillations of magnetization are determined for four cases of the magnetic crystallographic anisotropy near the transition instability region depending on the ratio between disk dimensions and current density. It is shown that the region of disk magnetization instability corresponds to the minimum values of the current density that are necessary for excitation of the oscillations or switching of magnetization. Depending on the value and direction of the anisotropy and the relaxation parameter, the frequency of the observed oscillations varies within 0.1-30 GHz.