Crystal Growth and Some Properties of Lead Indium Niobate-Lead Titanate Single Crystals Produced by Solution Bridgman Method

Abstract

A single crystal about 15 mm in diameter and 10 mm in length of the lead indium niobate-lead titanate, (1-x)Pb(In1/2Nb1/2)O3–xPbTiO3[PIN–PT(1-x/x)] solid solution system near a morphotropic phase boundary was obtained by the solution Bridgman method using PbO–B2O3 flux. X-ray diffraction study reveals that the ingot cut perpendicularly to the cylindrical as-grown PIN–PT(63/37)(the starting composition) single crystal length exhibits the (110) plane of the perovskite phase, and the wafers cut 2 mm and 10 mm from the bottom of the cylindrical PIN–PT single crystal exhibit the rhombohedral phase and tetragonal one at room temperature, respectively. The crystal growth was almost along the [110] direction. The Ti contents x of these wafers cut at 2 mm and at 10 mm were determined by Inductive Charge Plasma (ICP) chemical analysis to be 0.31 and 0.35, respectively. The Ti content of the as-grown PIN–PT(63/37)(the starting composition) single crystal was found to increase with growth away from the nucleation point. For x=0.31, the relative permittivity εr has a peak (37000 at 10 kHz) at the Curie temperature Tc, 300°C and then a shoulder at the ferroelectric rhombohedral to tetragonal phase transition temperature, 120°C with cooling. For x=0.35, the εr has a peak (25000 at 10 kHz) at Tc, 313°C.