Spin wave generation via acoustically-driven ferromagnetic resonance in a ferromagnetic insulator Y₃Fe₅O₁₂ on LiNbO₃

Spintronic devices employing spin waves, a propagating excitation of a spin lattice, are a promising platform to achieve low loss spin information transport.^1-4 To realize such devices, generation and detection of spin waves is an ongoing challenge that has been addressed in various ways. One approach to detect spin wave launching is via acoustically-driven ferromagnetic resonance (ADFMR), ferromagnetic resonance induced by surface acoustic waves (SAWs). However, most ADFMR devices are based on ferromagnetic metals which suffer from short spin coherence length.^5,6 In this study, we demonstrate the launching of spin waves via ADFMR in a ferromagnetic insulator (Y₃Fe₅O₁₂; yttrium iron garnet, YIG), which has a longer spin coherence length. Interdigitated transducers were used to excite SAWs on piezoelectric LiNbO₃ substrates patterned with YIG. The transmitted signal shows absorption at the resonant frequency when measured by a vector network analyzer. Angle-dependent measurements of ADFMR suggest this absorption is due to spin wave generation. We will also discuss detection of spin wave propagation through the YIG layer using the inverse spin Hall effect. These results open the possibility of developing spin wave materials and devices for efficient spin information transport.