Journal of Crystal Growth, Vol.312, No.7, 971-977, 2010
High-pressure vertical Bridgman growth of lead magnesium niobate-lead titanate single crystal
A modified high-pressure vertical Bridgman (HPVB) method has been used to grow single crystals of lead magnesium niobate-lead titanate (PMN-PT) using self-seeding. The starting charge was prepared close to stoichiometric composition of (1-x)Pb(Mg1/3Nb2/3)O-3-xPbTiO(3), ranging from x=0.29 to x=0.32. The ingots grown had a top diameter of similar to 114 mm and weighing similar to 1.9 kg with a volume of similar to 230 cc. Standard form off-the-shelf platinum crucibles from vendors with a wall thickness similar to 0.34 +/- 0.01 mm were used. The thinner platinum helped to attain a larger radial thermal gradient as well as enhancing the cost effectiveness of the process by reducing usage of precious metals. An oxygen partial pressure of 8000-10 000 ppm was used and controlled during the entire growth process. Self-seeding technique was used in order to attempt to grow large diameter single crystals of PMN-PT. The composition variation in the ingot is dependent on the growth rate, thermal gradients and oxygen partial pressure. The segregation coefficient of Ti was 0.86 +/- 0.008 for the starting composition of x=0.32. (C) 2010 Elsevier B.V. All rights reserved.