Four-magnon amplification and generation of spin waves in ferrite films

The possibility to generate the microwave radiation due to the nonlinear four-magnon interaction of magnetostatic spin waves in ferrite films has been considered. To attain phase synchronism in the film, the presence of a periodic structure in it has been assumed. It has been found that there are bias field ranges of 2.22–2.25 and 2.35–2.5 kOe (at a frequency $\omega$ = 6.5 $\times$ 10$^9$ s$^{-1}$) in which the parametric amplification can be effectively controlled by varying both the external magnetic field and the pump wave energy. Conditions have been determined for parameters of the structure (parametric amplification, absorption period, active-element length, and detuning), at which the generation is possible.