Synthesis, magnetic properties and spin-wave propagation in thin Y₃Fe₅O₁₂ films sputtered on GaN-based substrates

We describe the synthesis of submicron Y₃Fe₅O₁₂ (YIG) films sputtered on GaN-based substrates and present the results of the investigation of ferromagnetic resonance (FMR) and spin wave propagation in YIG / GaN structures. It is found that spin waves propagated in deposited YIG films have low damping. At the frequency of 3.2 GHz the spin-wave damping parameter is less than $3.4\cdot {10}^{-4}$. Sputtered YIG films have magnetic inhomogeneity, which gives the main contribution to the FMR linewidth. The FMR linewidth increase caused by the relaxation process is insignificant and is equal to low values (2.2–3.7% of the linewidth). The low relaxation of spin waves in deposited YIG films gives the opportunity to construct tuneable spin-wave band-pass filters with a high-quality factor on GaN substrates and to design radiation-tolerant monolithic microwave integrated circuits. (paper)