Morphological aspects of flux grown 0.91PZN-0.09PT crystals

The nucleation and growth of 0.91PZN-0.09PT single crystals was investigate d by the slow-cooling flux technique using PbO flux and by means of hot-sta ge microscopy. The results showed that during the initial stages of cooling small crystals of cubic morphology nucleated first. On further cooling, pr eferential growth developed along the four (1 1 1) corners of the cubic cry stals, and one of the corners eventually outgrew the rest into a large arro whead-shaped crystal against the heat flow direction. The terrace nature of the arrowhead crystals suggests that kinetic roughening, possibly promoted by a critical supersaturation in the solution, is the mechanism of the fas t growth of PZN-PT crystals. The present work shows that under favorable co nditions, such as with a high inverse temperature gradient and a solution c ooling rate of about 1 degrees C/h, large-sized PZN-PT crystals measuring 3 .0 x 2.5 x 2.0 cm(3) can be reproducibly grown from PbO flux by the slow-co oling technique. (C) 2000 Elsevier Science B.V. All rights reserved.