Nonlinear theory of the excitation of spin waves in ferrites by a longitudinal ultrahigh-frequency magnetic field

The problem of parametric excitation of spin waves in ferrites due to the action of a perturbing super high-frequency (SHF) magnetic field polarized along the direction of the constant magnetic field H₀ is considered in a nonlinear approximation. Such an examination enables one to determine the conditions for parametric excitation of spin waves and to find the amplitude and phase of the oscillations of the system's magnetization in the steady state. The frequency interval, within whose limits parametric excitation of spin waves is possible, is determined. Stability of the steady state under the conditions of parametric resonance is investigated. The results obtained are compared with existing experimental data.