Structural and Dielectric Investigation of the PbTiO ₃ ‐BaZrO ₃ System

Thermal expansion measurements, dielectric measurements, and X‐ray diffraction studies were made of the PbTiO 3 ‐BaZrO 3 system. A dielectric constant maximum of 11,300 was found at the Curie temperature for the Pb 0.80 ‐Ba 0.20 Ti 0.80 Zr 0.20 O 3 composition. The transition from a ferroelectric tetragonal phase to a para‐electric cubic phase for the 10, 20, and 30 mole % BaZrO 3 in PbTiO 3 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 % BaZrO 3 .