BULK SINGLE-CRYSTAL GROWTH OF BI12TIO20 BY THE CZOCHRALSKI METHOD

We have confirmed that photorefractive Bi12TiO20(BTO) crystal has incongruent melting properties and the upper limit for growing BTO single crystals is found to be 11 mol% TiO2. BTO single crystals 20 mm in diameter and 30 mm in length are successfully grown from a Bi2O3-rich melt by the Czochralski method. These crystals are light brown in color and transparent in the range over the absorption edge, near 450 nm. Growth rates of less than 0.5 mm/h prevent the grown crystal from excess Bi2O3 as inclusions. Facet and core characteristics are found to be dependent on the growth directions.