The effect of parametric processes on the propagation of spin waves in cross-shaped structures based on waveguides from yttrium iron garnet films

Topic. In this work, we experimentally explore the spin waves (SW) propagation in tangentially magnetized cross-like structure in the shape of two orthogonal waveguides on the base of yttrium iron garnet (YIG) film for the conditions when the first order parametric processes take place. Aim. We studied the influence of parametric processes on spectrum of SW in the tangentially magnetized cross-like structure in the filtration band defined as the frequency interval $\Delta f_{||,\perp}$ of the overlapping spectra of SWs in longitudinally and transversely magnetized waveguides. Methods. The experiments were carried out with the cross-like structure from YIG film with the thickness $d\approx3.8\mu$m, having the form of two orthogonal waveguides with the width $w\approx500\mu$m, length $L\approx3$ mm, and wire SW antennas placed at the ends of waveguides. One of the antennas was considered as the input and was used to excite SW in the structure, and the other three were used to analyze the spectrum of output signals with the frequencies inside the filtration band $\Delta f_{||,\perp}$. Results. It was shown that the shape of SW spectrum obtained at the output antennas of orthogonal waveguides could significantly change when the SW parametric instability takes place. Discussion. We attribute this effect to the formation mechanism of secondary SW-satellites in the spectrum of the pump signal and the influence of lateral quantization effects on SW spectrum in the studied cross-like structure.