Crystal Growth and Dielectric Properties of Solid Solutions of Pb(Yb1/2Nb1/2)O3–PbTiO3 with a High Curie Temperature near a Morphotropic Phase Boundary

Abstract

The Pb(Yb_1/2Nb_1/2)O₃–PbTiO₃ (PYN–PT) binary system single crystal near the morphotropic phase boundary (MPB) composition with (100) planes of 1–2 mm length on one side was successfully grown by the flux method using PbO–PbF₂–B₂O₃ flux. The PYN–PT (47/53) single crystal was found, by simultaneous microdifferential thermal analysis and thermogravimetric analysis, to show a peritectic melting point at 1205°C with a decomposition of the perovskite crystals into a pyrochlore phase and a liquidus point at 1253°C. The structure of the PYN–PT (47/53) single crystal was determined by X-ray diffraction study to be tetragonal with a=4.05±0.01 A and c=4.14±0.01 A at room temperature. The PYN–PT single crystal shows the maximum value of the relative permittivity ε _r of 16000 at 1 kHz at a Curie temperature T _c of 404°C, which is as high as that in the Pb(Zr, Ti)O₃ system near the MPB and the value of the remanent polarization P _r of about 26 µC/cm² at 140°C.