Two-dimensional magnons and domain wall dynamics in yttrium iron garnet

Interactions between different types of excitations in magnetic domain walls in YIG single crystal plates are investigated by induction and magnetooptic techniques. The behavior of translational and flexural modes of the wall vibrations as a function of wall velocity was found to be asymmetric. The flexural mode amplitudes and eigenfrequencies for positive and negative wall velocities are not equal, and the dynamic structures of the wall moving at positive and negative velocities are found to be essentially different. The character of both asymmetries was reversed by changing the wall polarity. Various nonlinearities in highly excited domain walls were studied, including the appearance of multiple discrete harmonics as well as a continuous component of the Fourier spectrum of the wall vibration signal and the corresponding changes of its mobility and dynamic structure