Thermodynamic theory of the lead zirconate-titanate solid solution system, part II: Tricritical behavior

Abstract

Two tricritical points, where a phase transition changes from first to second order, were found to occur in the lead zirconate-titanate (PZT) solid solution system. High-temperature x-ray diffraction data on sol-gel derived PZT powders were used to calculate the cell parameters and spontaneous strain in the ferroelectric phases. These data were used with addition data from the literature to determine values of the higher-order dielectric stiffness coefficients, which were then used to locate the tricritical points. The values of the coefficients are also needed in the development of a thermodynamic theory of the PZT system.