MPB design and crystal growth of PMN–PT–PZ relaxor ferroelectrics

Abstract

Rhombohedral–tetragonal ferroelectric structural phase transition temperature (TR−T), far below the Curie temperature (Tc) in lead magnesium niobate–lead titanate (PMN–PT) relaxor ferroelectric single crystal, heavily restricts its further applications either as a sensor or transducer. To overcome this shortcoming, lead zirconate (PZ) was introduced into the PMN–PT pseudo-binary system to increase TR−T via the morphotropic phase boundary (MPB) composition design and optimization. According to the PMN–PT–PZ pseudo-ternary phase diagram, various compositions have been selected to discuss the relations between their phase structural transition and piezoelectric properties in the PMN–PT–PZ pseudo-ternary system. X-ray diffraction (XRD) investigation indicates clearly that PMN–PT–PZ ceramics with MPB compositions experience a typical structural phase transition process from rhombohedral phase to tetragonal phase. Remnant polarization (Pr=33.4μC/cm2) and piezoelectric coefficient (d33=1050pC/N) were obtained at the (001) cut PMN–PT–PZ single crystal. TR−T was increased up to 120°C by measuring its dependence of dielectric constant on temperature.