Bridgman growth of strontium barium niobate single crystals

Abstract

Vertical Bridgman growth of single crystals of Sr1−xBaxNb2O6 is reported for the first time. Large 25 mm diameter crystals of the congruent composition Sr0.61Ba0.39Nb2O6 have been grown in the 〈0 0 1〉 direction at growth rates of approximately 1 mm/h. Stable growth has been achieved at rates up to about 12 mm/h. Striations and diameter control problems have been virtually eliminated by using this growth method. By modulating the furnace setpoint to intentionally produce striations, the relationship between the induced temperature fluctuations and refractive index striations as well as the interface shape and microscopic growth rate were determined. Surface and core defects were also investigated. The results presented here demonstrate the feasibility of large-scale growth of high optical homogeneity crystals of strontium barium niobate.