Dielectric, pyroelectric and piezoelectric properties of calcium-modified lead magnesium tantalate-lead titanate ceramics

Dielectric, pyroelectric and piezoelectric properties of relaxer ferroelectrics in solid solution, formulated 0.65(Pb1-xCax)(Mg1/3Ta2/3)O-3-0.35PbTiO(3), have been investigated. Complete single-phase perovskite with high density was obtained with all samples fired at 1250 degrees C. The Curie temperature and pyroelectric peak temperature decrease almost linearly as the amount of Ca in the compositions increases. The transition temperature of the solid solutions can easily be controlled by Ca additions in the PMT-PT. Dielectric, pyroelectric and piezoelectric constants achieved maximum values for x=0.02. Compositions near 0.65PMT-0.35PT-0.12Ca have been identified to have high dielectric constants (similar to 15000) and low dissipation factors (similar to 0.015) near room temperature.