Morphological aspects of flux grown 0.91PZN-0.09PT crystals

Abstract

The nucleation and growth of 0.91PZN–0.09PT single crystals was investigated by the slow-cooling flux technique using PbO flux and by means of hot-stage microscopy. The results showed that during the initial stages of cooling small crystals of cubic morphology nucleated first. On further cooling, preferential growth developed along the four 〈111〉 corners of the cubic crystals, and one of the corners eventually outgrew the rest into a large arrowhead-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 fast growth of PZN–PT crystals. The present work shows that under favorable conditions, such as with a high inverse temperature gradient and a solution cooling rate of about 1°C/h, large-sized PZN–PT crystals measuring 3.0×2.5×2.0cm3 can be reproducibly grown from PbO flux by the slow-cooling technique.