Non-linear instability under resonance

The nonlinear instability threshold of acoustic modes being in phase synchronism with exchange spin modes has been investigated experimentally. Experiments were made in planar ferrite film - dielectric substrate structures in the range of magnetic fields and frequencies where exchange MSW (spin-wave resonances) are in phase synchronism with transversal acoustic waves (i.e. spin-wave resonances have the same wavelength as transversal acoustic modes wavelength). Strong oscillations of the nonlinear threshold has been revealed in the narrow range of the spectrum which are due to strong reconstruction of the spectrum which results in reconstruction of the each mode and the secondary waves modification.