Propagation of surface acoustic waves in magnetic bubble garnet films

Surface Acoustic Wave (SAW) delay lines have been fabricated on magnetic bubble garnet films. Interdigital transducers on a piezoelectric layer (zinc oxide film sputtered on top of the garnet film) have been used for acoustic wave generation and detection. Amplitude and phase delay variations of the SAW delayed signal were measured as a function of an externally applied dc magnetic field. The maximum change in the SAW propagation properties was observed when the applied field H was parallel to the SAW propagation vector k, and at field strengths of the same order as that required for FMR at the operating frequency. The results are explained qualitatively in terms of an approach which provides an explanation for the dependence of the SAW measurements on the orientation and magnitude of the applied field.