Refined Position of Morphotropic Phase Boundary and Compositional Optimization of Pb(Mn1/3Nb2/3)O3–PbZrO3–PbTiO3 Solid Solutions

The morphotropic phase boundary (MPB) for high-density solid solutions with compositions of x Pb(Mn 1/3 Nb 2/3 )O 3 – y PbZrO 3 – z PbTiO 3 (PMnNZT) with x = 0.02–0.16, y = 0.42–0.56, and z = 0.42–0.56 has been refined on the basis of an analysis of the dielectric and piezoelectric properties of the fabricated samples. An X-ray diffraction analysis of the PMnNZT solid solutions suggested that the refined rhombohedral-tetragonal MPB in this material system is in the compositional region x = 0.02–0.134, y = 0.42–0.54, and z = 0.44–0.485. It was found that a hard-mode solid solution with x = 0.10, y = 0.45, and z = 0.45, which lies in the refined MPB region, exhibited excellent piezo- and ferroelectric properties highlighting its potential as a high-power piezoelectric material for ultrasonic vibrators and piezoelectric transformers.