METASTABLE CRYSTAL-GROWTH OF THE LOW-TEMPERATURE PHASE OF BARIUM METABORATE FROM THE MELT

Single crystals of the low temperature phase of barium metaborate (beta-BaB2O4) were grown successfully by means of the Czochralski method at 1048-degrees-C. The growth temperature was far above the alpha-beta transition temperature (920-degrees-C) and the growth process is a metastable one. A high temperature, X-ray examination proved that the metastable state of the beta phase directly crystallized from the melt at 1048-degrees-C. The homogeneous temperature distribution in the crystal is thought to be important for the beta phase stability above the alpha-beta transition temperature.