Micromagnetic modeling of nonlinear interaction of lateral magnetostatic modes in cross-shaped structures based on waveguides from iron yttrium garnet films

Topic. In this work, parametric processes in the system of predominantly dipole magnetostatic waves (MSW) in the cross-shaped structure from two orthogonal waveguides of iron yttrium garnet film magnetized by the in-plane field $H = 460$ Oe and having microstrip transducers at its ends are considered. One of the antennas at the end of the transversely magnetized waveguide was assumed as an input and was used to excite MSW with the frequency of 3 GHz. Aim. The goal was to analyze the spectral and amplitude characteristics of MSW using the output antennas, depending on the amplitude of the excitation field, to identify features of the second order parametric processes in cross-like structure. Methods. To deal with the problem we used micromagnetic simulations solving the Landau–Lifshits equation by a finite-difference method using the OOMMF software. Results. It is shown that when the input signal amplitude exceeds the certain threshold, the dependence of the output MSW amplitude on the input amplitude becomes significantly nonlinear. This is accompanied by the appearance of intensive satellites in the spectrum located symmetrically with respect to the pump frequency at distances from tens to hundreds of MHz. These changes are associated with the second order parametric instability emerging in the system of lateral modes in the crossing waveguides. Discussion. The obtained results can be used for the development of structures based on spin waveguides' networks for multi-level reverse logic devices.