Piezoelectric and Ultrasonic Studies of Mixed CuInP₂(S_XSe_{1 - X})₆ Layered Crystals

Abstract

Results of ultrasonic and piezoelectric properties investigation of mixed CuInP ₂ (S _X Se _{1 − X} ) ₆ layered ferroelectric single crystals are presented. The piezoelectric detection of longitudinal ultrasonic signal by thin plates of CuInP ₂ (S _x Se _{1− x} ) ₆ crystals (x = 0.05, 0.1, 0.2 and 0.25) was observed and the temperature dependencies of piezoelectric properties have been studied. The piezoelectric sensitivity decreased upon heating and vanished at higher temperature, where crystals exhibit phase transition (PT) to centrosymmetric phase. At transition temperatures the anomalies of ultrasonic velocity and attenuation have been observed. At room temperature, above PT, the electrostriction-induced piezoelectricity was observed under DC bias electric field applied along c-axis of the CuInP ₂ (S _x Se _{1− x} ) ₆ crystals.

Keywords:

• Ferroelectrics
• phase transitions
• ultrasonic and piezoelectric measurements

Acknowledgment

Support of Lithuanian State Science and Studies Foundation under the project T-19/06 is gratefully acknowledged.