Width-mode order dependent spin wave conversion in an in-plane magnetized microscale T-shaped YIG magnonic splitter

As one of the fundamental magnonic devices, magnonic splitter devices have been proposed and spin wave propagation in the devices has been studied numerically and experimentally. In the present work, we fabricated a T-shaped magnonic splitter with three 6 μm-wide arms from a 100 nm-thick yttrium iron garnet film. Using time-resolved magneto-optic Kerr microscopy, we observed spin waves splitting into both, the vertical and the horizontal direction at the junction. Analyzing the results, we found that the spin wave width modes are converted into each other during the splitting process and, consequently, concluded that the width mode conversion efficiency depends on the ratio of wavelength to the vertical branch's width and the anisotropic distribution of the spin wave amplitude at the T-junction.