Nonlinear damping of high-power magnetostatic waves in yttrium–iron–garnet films

The nonlinear decay of continuous-wave magnetostatic surface wave and backward volume wave signals has been measured for propagation in a narrow 6.9 μm thick yttrium–iron–garnet film strip, with excitation frequencies and wave numbers between 5470 and 5630 MHz and 47 and 216 rad/cm, respectively. The results show: (1) that the onset of nonlinear damping is a threshold effect, and (2) that a nonlinear decay model with two damping terms, one linear and one quadratic in the wave power, are needed to model the measured response.