Growth of high performance piezoelectric crystal Pb(Zn1/3Nb2/3)O3-PbTiO3 using PbO flux

Novel piezoelectric crystal (1 - x)Pb(Zn1/3Nb2/3)O-3-xPbTiO(3) (PZNT) has attracted much attention due to its high piezoelectric properties and potential applications in medical ultrasonic devices, sonar transducers, solid state actuators. However, the applications of PZNT crystals are limited by the lack of a simple and reproducible growth technique. In this work, large size PZNT crystals were grown by the vertical Bridgman method using 50 mol% PbO as a flux. The growth conditions were optimized as mole ratio of raw materials and flux = 1:1, soaking temperature 1150-1200 degrees C, soaking time 10 It, the lowering rate of the crucible 0.5 mm/h and the temperature gradient near solid-liquid interface about 50 degrees C/mm. The maximum size of as-grown PZNT crystal was about 60 min in length. The crystal was oriented and its piezoelectric constant d(33) and coupling coefficient k(33) were measured over 2000 pC/N and 0.92, respectively. (C) 2007 Elsevier B.V. All rights reserved.