SPIN-WAVE ENVELOPE SOLITONS IN THIN FERROMAGNETIC-FILMS (INVITED)

The process of spin-wave (SW) envelope soliton formation and propagation has been studied experimentally in thin yttrium-iron-garnet (YIG) films at microwave frequencies. The formation of solitons has been observed in perpendicularly and tangentially magnetized YIG films in the spectral regions of high dispersion near the "dipole gaps" in the dipole-exchange SW spectrum. With the increase of the input pulse duration or/and amplitude, the multisoliton regime of SW propagation and the regime of SW modulational instability have been observed. With a further increase of input power the spectrum of SW modulational instability became more complicated and a SW strange attractor was formed through the destruction of two-frequency quasiperiodic motion. The theoretical interpretation of the observed nonlinear SW phenomena is given in the framework of nonlinear Schrodinger equation (NSE) model taking into account peculiarities of the thin-film dipole-exchange SW spectrum. The results of numerical calculations of SW envelope profiles performed using NSE model are compared to the results of the experiments.