Generation of Gigahertz Frequency Surface Acoustic Waves in YIG/ZnO Heterostructures

We study surface acoustic waves (SAWs) in yttrium iron garnet (YIG)/zincoxide (ZnO) heterostructures, comparing the results of a computationallylightweight analytical model with time-resolved micro-focused Brillouin lightscattering data. Interdigital transducers (IDTs), with operational frequenciesin the gigahertz regime, were fabricated on 50 and 100nm thin films of YIGprior to sputter deposition of 830nm and 890nm films of piezoelectric ZnO. Wefind good agreement between our analytical model and micro-focused Brillouinlight scattering data of the IDT frequency response and SAW group velocity,with clear differentiation between the Rayleigh and Sezawa-like modes. Thiswork paves the way for the study of SAW-spin wave (SW) interactions in low SWdamping YIG, with the possibility of a method for future energy-efficient SWexcitation.