Collapse of the Nonlinear Spin Dipole Wave Pulses of the Millimeter Wave Range in the YIG Films

The spatiotemporal collapse of the spin-dipole wave pulses of the millimeter wave range is investigated theoretically. The dispersion and the diffraction coefficients of spin-dipole wave have been calculated, when the retardation has been taken into account. It is demonstrated that YIG films are suitable for observing the wave collapse in the millimeter wave range, due to low dissipation and quite high values of dispersion and diffraction coefficients. In the hexaferrite films, despite the higher values of the dispersion and the diffraction coefficients, the dissipation prevents the formation of the spatiotemporal collapse. The additional focusing of the pulse can increase the nonlinear pulse compression. The numerical simulations have confirmed this result.