Low temperature piezoelectric displacement characteristics of (1-x)BiFeO₃-xBiCoO₃ measured with twin laser doppler vibrometer

Abstract

To investigate the lead-free piezoelectric materials, an evaluation system of the electric and piezoelectric properties at low temperature is required, because some prepared samples, such as BiFeO3, show high leakage current at room temperature. We have developed a light transmission type vacuum chamber system with the twin beam laser doppler vibrometer at wide temperature (-190 ~ +200 oC) and measurement frequency (max. 100kHz) range. In this study, we have investigated the ferroelectric and piezoelectric characteristics of the (1-x)BiFeO3-xBiCoO3(x = 0~0.3) thin films at liquid nitrogen temperature (-190oC) with high measurement frequency. As a result, we have gained the P-E hysteresis curve and butterfly shaped longitudinal displacement curve at -190oC with 5 kHz.