Structural and Dielectric Investigation of the PbTiO3-BaZrO3 System

Thermal expansion measurements, dielectric measurements, and X-ray diffraction studies were made of the PbTiO₃-BaZrO₃ system. A dielectric constant maximum of 11,300 was found at the Curie temperature for the Pb_0.80-Ba_0.20Ti_0.80Zr_0.20O₃ composition. The transition from a ferroelectric tetragonal phase to a para-electric cubic phase for the 10, 20, and 30 mole % BaZrO₃ in PbTiO₃ compositions was of first order. X-ray diffraction determination of the lattice parameters (25°C) showed that this tetragonal-to-cubic phase transition occurred at a composition of 44 mole % BaZrO₃.