SPIN WAVES PARAMETRIC AUTORESONANCE

This paper is devoted to the investigation of parametric autoresonance of spin waves in ferromagnets with easy-axis anisotropy. It is assumed that both the constant and alternating magnetic fields are oriented along the anisotropy axis. The threshold values of the amplitude of the alternating magnetic field required for
autoresonance excitation have been determined. It is shown that the autoresonance perturbation at the final stage transforms uniform spin oscillations into a spin wave. In the intermediate stage of the transformation process, near the resonance region, stable, highly nonlinear structures of the dark soliton type are formed. The influence of dissipation on the autoresonance process is discussed.