Temperature and electric field dependence of ultrasonic wave propagation and attenuation in PZN-PT single crystal in vicinity of a phase transition

Abstract

The longitudinal and transverse modes of ultrasound propagation in Lead Zinc Niobate–Lead Titanate (PZN–PT) single crystal solid solutions are investigated as a function of temperature. The influence of an electric DC bias field on the elastic stiffness at various temperatures is studied. The presence of more stable phases induced by this electric field is observed. The polarization directions are modeled in terms of free energy function. The experiments are conducted in a dedicated temperature chamber working in a wide temperature range from 200 up to 470 K for ultrasonic measurements thin plate samples with the option for DC bias fields. The bias field was applied by a high voltage amplifier Trek model 610D. Crystal cuts of [001], [110] and [111] were used for the study of electric field poling conditions and temperature influence on structure induced by polarization orientation. A study of anomalies in sound velocity and relative attenuation near ferroelectric transitions is performed. It is well established that near the temperature of a second-order structural phase transitions, and in particular near the Curie point of ferroelectrics, anomalously strong ultrasonic absorption occurs.