Amplitude and phase modulation of SH waves by resonant scattering at PZT-5A/BaTiO₃ imperfect boundary

This study investigates the reflection and refraction behaviour of shear-horizontal (SH) waves at the interface of PZT-5A and BaTiO₃. The interface is modelled by an electrically induced classical spring and a piezoelectric membrane. An analytical framework is used to assess how interfacial mechanical and electrical stiffnesses, together with piezoelectric coupling, influence the amplitude and phase of reflected and transmitted SH waves. Results indicate that increased mechanical stiffness amplifies reflected SH-wave intensity while diminishing refraction and electro-acoustic conversion, whereas stronger electrical coupling facilitates enhanced refraction with reduced reflection. Notably, resonance phenomena near grazing incidence yield pronounced amplitude peaks and abrupt phase shifts, highlighting the sensitivity of wave behaviour to incident angle and interfacial properties. These findings provide useful guidance for the design of acoustic filters, waveguides, sensors and non-destructive evaluation components, and may be extended to multilayered or frequency-dependent systems in future work.