Leaky surface acoustic waves on langasite with thin dielectric films

The propagation characteristics of leaky surface acoustic waves on rotated Y-cut langasite with a thin dielectric film, such as those of tantalum pentoxide (Ta₂O₅) and silicon dioxide (SiO₂), are investigated theoretically and experimentally, mainly in terms of the attenuation. The theoretical analysis showed that, for a certain range of the cut angle, the attenuation can be reduced by choosing the appropriate material and thickness of the film. In fact, the estimated propagation loss of the leaky surface acoustic wave on (0°, 140°, 67°)-cut langasite with RF-sputtered Ta ₂O₅ film decreased to approximately one-third in comparison to those of the sample without the thin film