Brillouin Light Scattering and Magnon Wave Vector Distributions for Microwave-Magnetic-Envelope Solitons in Yttrium-Iron-Garnet Thin Films

Brillouin light scattering has been used to measure wave number k_m and wave vector k_m angle distributions for 5 GHz magnetostatic backward-volume-wave envelope solitons in yttrium-iron-garnet thin films. For moderate powers, the data revealed spin waves directly associated with the solitons with k_m values in the ±300 rad/cm range. For high powers, the data showed high k_m spin waves in the 2500–5000 rad/cm range with discrete in-plane k_m directions at 90° and other angles around 90° relative to the soliton propagation direction. These high k_m spin waves provide the first direct evidence of spin wave shedding associated with solitons at high powers.