Optimization of poling parameters of mechanically processed PLZT 8/60/40 ceramics based on dielectric and piezoelectric studies*
1 Ceramics and Composites Group,
Defence Metallurgical Research Laboratory, 500058
2 School of Physics, University of Hyderabad, 500046 Hyderabad, India
Received in final form: 22 July 2015
Published online: 3 November 2015
Ultra high strain (Pb0.92La0.08)(Zr0.60Ti0.40)O3 (PLZT 8/60/40) piezoelectric ceramics were synthesized by high energy ball milling method to study the relation between poling conditions (poling electric fields, times and temperatures) and electrical properties. The ceramics were structurally investigated and with the help of ferroelectric P-E hysteresis loop, coercive field was determined. This study deals with the identification of optimum poling conditions and their effect on the piezoelectric and dielectric properties mechanically synthesized PLZT 8/60/40 ceramics. Different combinations of poling parameters were used to measure the values of dielectric constant, dielectric loss, piezoelectric charge (d33) and electromechanical coupling coefficients (kp). These values show that a ferroelectric material can be poled at ~5 kV/cm (<0.5Ec), contrary to common practice of poling far above the coercive field. The effect of aging on the electrical properties was also studied for ceramics poled at 0.6Ec and 3Ec. With the help of this study, poling electric field as well as another two important poling parameters, viz poling temperature and poling time, were optimized. Optimum poling temperature was found to be in the range of 75 °C to 125 °C with optimal poling time of 30 min. Additionally the effect of ceramic sample thickness on the said properties was also studied. The maximum d33 and kp values for PLZT ceramics was found to be ~715 pC/N and ~77%, respectively.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2015