Nonlinear spin waves in dynamic magnonic crystals created by surface acoustic waves in yttrium iron garnet films

Experimental results on the influence of the intensity of surface magnetostatic spin wave (SMSW) on its propagation in the dynamic magnonic crystals (MCs) created by surface acoustic waves (SAW) propagating in yttrium iron garnet (YIG) film on the gallium gadolinium garnet (GGG) substrate are presented. The shift of the resonant frequency of the SMSW reflections (frequency of the magnonic gap) and widening of the resonant reflection curves (increasing the width of the magnonic band gap) from their former meanings (3730 MHz and 5.25 MHz, respectively) were observed at 20 MHz SAW of 20 mW in biasing magnetic field of 640 Oe at input microwave power exceeding the threshold value of −5 dBm. At the input power of 10 dBm, the deviations of the magnonic gap frequency and of the width of the SMSW resonant reflected curves reach the values of 5 MHz and 2 MHz, respectively. At a frequency of 3730 MHz, a decrease in the reflection coefficient of the SMSW was observed at the input powers above the threshold. These results may be useful in investigations of MC and for creating new nonlinear signal processing devices.