Investigation of Nonreciprocal Characteristics of Spin Waves in Their Interaction with a Weakly Contrasting Magnon Crystal

The spatial-frequency distributions of spin waves in a magnon crystal and their dispersion characteristics were experimentally investigated. In spite of the weak energy contrast of the crystal, the formation of a number of Brillouin zones and the existence of two types of wave nonreciprocity were detected. Of the two types, one is due to the asymmetry of dispersion dependences with respect to the direction of wave propagation, and the other is due to the difference between the spatial distributions of the waves propagating in opposite directions. The magnon crystal made it possible to detect and measure these types of nonreciprocity.