High electromechanical coupling in PZT epitaxial thick film resonators at 550 ºC

A shift of Curie temperature is reported only in a very thin epitaxial film. In this study, unusual high temperature shift of Curie temperature in thick PZT and PbTiO 3 film was demonstrated. Thickness extensional mode electromechanical coupling coefficient k t of the films were extracted from high-overtone bulk acoustic resonator structure. Thick PZT epitaxial (with 4.4 μm) films exhibit high k t of 0.30 at 500 °C and 0.37 at 550 °C. Moreover, high k t of 0.42 was also observed in thick PbTiO 3 film (with 2.8 μm) at 550 °C.