Thermal tuning of acoustic transmission enhancement through a phononic crystal slab

This paper describes the thermal tuning of acoustic transmission enhancement through a phononic crystal slab (PCS), which is formed by ferroelectric ceramic Ba_0.7Sr_0.3TiO₃ (BST) slab patterned with periodical array of rectangular gratings on one side. We theoretically investigate the normal incident transmission spectrum of the PCS in the temperature of 35°C and 45°C respectively, which are across Curie temperature (T_C). A remarkable transmission peak originating from the excitation of A₀ Lamb mode at frequency of 0.37 MHz changes to the frequency of 0.44 MHz over 10°C temperature range, which is due to the high thermal sensitivity of acoustic velocities in BST across T_C. The shift of the transmission enhancement enables the proposed PCS promising as a temperature-tuned multi-frequency Lamb wave filter or switch.