IMF2017

In recent years, an important fact which has drawn much attention in the field of ferroelectrics is electrocaloric effect (ECE). In this study, we report the change in electrocaloric effect due to the change in doping concentration of La in PZT. In order to do this, PZT (65/35) with La 6, 7, 8 and 9 % are prepared using alkoxide route of sol-gel synthesis, followed by heat treatment at 700 °C. Samples are sintered using a specially designed double atmospheric layer protected sintering method to protect lead loss at high temperatures. The morphological study and phase confirmation are carried out using scanning electron microscopy and X-ray diffraction respectively. The dielectric measurements are done in the frequency range from 100 Hz to 10 MHz at different temperatures from -50 °C to 300 °C. Polarization (P) vs. electric field (E) measurements are carried out in the required temperature range to calculate the ECE. The relation between strain and relative permittivity with electric field are analyzed from P-E measurements. The piezoelectric properties are also studied at room temperature. High value of ECE in the vicinity of room temperature is desirable for practical applications. For a material, ECE is highest around its Curie temperature. The Curie temperature of the PZT (65/35) is found to decrease with increasing La concentration, which in turn makes the material more suitable for refrigeration and other applications near room temperature.