Refined phase portrait of the rhombohedral region of the x–T diagram of the Pb(Zr1–x Ti x )O3 system and singularities of dielectric spectra of its solid solutions

Abstract

The boundaries of the phase states of solid solutions in the rhombohedral region of the Pb(Zr 1 -x Ti x )O 3 (0 ≤ x ≤ 1.00) system and the curve of the R3c → R3m phase transition have been refined on the basis of detailed (with a small concentration step) high-temperature (25°C ≤ T ≤ 700°C) studies of the structural characteristics and frequencies of the piezoelectric resonance of the radial oscillation mode of polarized ceramic samples. It has been shown that, in the range 0.07 ≤ x ≤ 0.20, the transition curve practically coincides with the generally accepted one and, in the interval 0.20 ≤ x ≤ 0.36, it differs from the latter by a nonmonotonic behavior and agrees in the boundaries and regions of the phase states. The curve of the transition from the region of coexistence of the R-and Rh 1 -phases in the clusterized state to a region with single Rh 1 -phase in the interval of concentrations 0.08 ≤ x ≤ 0.12 and temperatures 200-250°C has been constructed. The full x-T phase diagram of the Pb(Zr 1 -x Ti x )O 3 system has been presented. Dispersion spectra of solid solutions on variation in the frequency of the measuring electric field in the interval of 25-10 6 Hz have been studied, and their correlation with singularities of the phase portrait has been established.