Theory of bistable magnetostatic surface waves

A comprehensive theory of nonlinear magnetostatic wave propagation in a corrugated ferromagnetic film is presented. The applied magnetic field is in the plane of the film, and is perpendicular to the propagation direction. A portion of the film has its upper boundary periodically corrugated, and an analysis close to the Bragg condition is carried out. Typical bistable loops of output power against input power are obtained. Multistability is predicted for input powers, in the range 50-150 mW/mm. The threshold power is rather sensitive to the modulation of the upper surface, i.e., to the amplitude of the geometric variations on the periodic surface. Small amplitudes suppress the multistability and this critical region is investigated quantitatively. It is concluded that the multistable effects should be readily observable