Effect of calcium addition on microstructure and electrical properties of lead zirconate titanate ceramic compositions near MPB

Calcium modified lead zirconate titanate ceramic compositions Pb(1-x)CaxZr0.52Ti0.48O3, where x=0, 0.02, 0.04, 0.06, 0.08, 0.1, have been prepared by solid state reaction method using wet milling. Scanning Electron Microscopy (SEM) studies have been carried out to see the variation in the grain size with calcium addition. A correlation of the dielectric constant and dielectric loss with grain size effect is presented in this paper. A monotonic decrease in the transition temperature along with more diffuseness in paraelectric-ferroelectric phase transition is observed with increasing calcium content. The values of activation energy (E-a) for the samples, calculated for ferroelectric region near phase transition temperature, are found to be in the range of approximately 0.6-1.0 eV which reflects that the main charge carriers responsible for conduction at higher temperatures are oxygen ion vacancies.