  A possibility is discussed of observing spin injection effect on the
ferromagnet domain structure by means of resonant excitation of the domain wall
oscillations by a spin-polarized ac injection current. The natural frequency of
the domain wall oscillations in a thin ferromagnetic film with parallel
anisotropy is calculated. Amplitude of the domain wall forced oscillations
excited by the spin-polarized ac current is determined. Then effect of such
oscillations on the current is considered and appearance of nonlinear phenomena
such as rectification of the ac current and second harmonic generation is
predicted.
