Growth of bismuth tellurite crystals by vertical Bridgman method

The growth of bismuth tellurite crystals by the modified vertical Bridgman method has been reported in this paper. The volatilization of melt is avoided by sealing the double-shell platinum crucibles and the cracking of crystals is decreased under smaller temperature gradients in the Bridgman furnace. By means of the optimum conditions such as stoichiometric feed materials, growth rate of 0.5-0.8 mm/h and the temperature gradient of 30-35 °C/cm across the solid-liquid interface under the furnace temperature of 980-1000 °C, the single crystals have been grown successfully by the vertical Bridgman method. Some technical problems such as composition of melt, seeding operation, cleavability and crucible corrosion are discussed. The Bridgman process is confirmed to be promising for growing high-quality crystals with improved physical properties.