Crystal growth and electrical properties of lead indium niobate-lead titanate binary single crystal

The largest Pb(In1/2Nb1/2)O-3-PbTiO3(PIN-PT) binary system single crystal ( about 20 mm x 10 mm x 5 mm, 4.5 g) near the morphotropic phase boundary com position with well-developed (1 0 0) planes was grown by the flux method us ing PbO-PbF2-B2O3 flux. The PIN-PT(72/28) single crystal was found by simul taneous microdifferential thermal analysis and thermogravimetric analysis t o show a peritectic melting at 1283 degreesC with a partial decomposition o f the perovskite crystal into a pyrochlore phase, followed by a liquidus po int at 1294 degreesC. The electromechanical coupling coefficient in rectang ular bar mode, k(33)' =78%, for phased array ultrasonic transducers was obt ained by using the rhombohedral PIN-PT(72/28) single crystal oriented along the [0 0 1] axis. k(33)' = 78% is the highest value reported so far among all the piezoelectric materials with a T-c > 250 degreesC and is almost ind ependent of temperature, and even at 200 degreesC decreased only by about 5 %. The piezoelectric constant d(33)=700pC/N was obtained. The relative perm ittivity E, decreases after poling. For instance, the epsilon (r) value of 2650 before poling, decreases to 1500 after poling. (C) 2001 Elsevier Scien ce B.V. All rights reserved.