Nonlinear magnonic coupler using backpropagating surface spin waves

We investigated a spin-wave propagation in a magnon-crystal structure formed from two lateral microwaveguides separated by a one-dimensional antidot array. The mechanisms of control of the backpropagating regime of the surface spin waves both with geometry tuning and with power level variation in the case of in-plane magnetization are investigated by the method of micro-magnetic modeling and the experimental method of Brillouin light scattering spectroscopy. It was shown that for the case of spin-waves propagation through the isolated channels the shape anisotropy in the coupling region can be tuned effectively by a variation of the distance between the channels. The regime of nonlinear switching of the signal and backward propagation was observed in microwave and Brillouin spectroscopy measurements. The proposed effect of the signal separation manifests itself in the spatially and frequency-selective regimes of spin-wave propagation. Proposed spin-wave coupler opens an alternative way for the design of the functional interconnections of spin-wave based units in the planar magnonic networks.