PMN-PT and PIN-PMN-PT single crystals grown by continuous-feeding Bridgman method

Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) and Pb(In1/2Nb1/2)O-3-Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PIN-PMN-PT) single crystals are superior piezoelectric materials. The single crystal boules grown by the Bridgman method include large property variation due to compositional segregation. We have developed the continuous-feeding Bridgman method to eliminate the compositional segregation. A long size PMN-PT single crystal boule (80 mm in diameter and 320 mm in length) was successfully grown under optimized growth conditions. The boule showed high property uniformity (10% in d(33) variation) as a result of high composition uniformity. This results in productivity enhancement of 24% compared to our conventional 220 mm long boules. Two PIN-PMN-PT single crystal boules each with different target composition were also successfully grown. They showed stable properties and also higher coercive field (Ec = 510-550 V/mm) than PMN-PT. One of the crystals exhibited a very high phase transition temperature (Trt = 134 degrees C). The PIN-PMN-PT single crystals produced during this study will be beneficial for high power or high temperature applications.