Thermal Induced Structural and Dielectric Anomalies in Calcium Modified Lead Titanate Ceramics

Abstract

Dielectric, structural and pyroelectric properties of the Pb0.525Ca0.475TiO3 (PCT47.5) ceramic system were investigated for temperatures ranging from cryogenic up to 570 K. Two anomalies were observed in the temperature dependence of the dielectric permittivity and of the pyroelectric coefficient. A structural refinement study based on the powder XRD data revealed that a distorted perovskite structure with orthorhombic symmetry in space group Pbnm was the best fitting for the entire temperature range analyzed. Nevertheless, the analysis protocol showed that the temperature dependence of the refined lattice parameters is very sensitive to the phase transitions, allowing the association of such transitions to the anomalies observed in the electric properties.