Growth of Bi12SiO20 single crystals by the pulling-down method with continuous feeding

Bi12SiO20 single crystals were successfully grown by the pulling-down method with continuous feeding. As-grown crystals were amber in color and transparent, and had no cracks or inclusions. A crystal with homogeneous composition was obtained from Bi-rich feed powder having a composition of 14.1 mol% SiO2, whereas precipitates of Bi4Si3O12 were observed on the surface of a crystal grown with stoichiometric powder. The shape of the solid-liquid interface during the crystal growth was estimated to be almost flat, which was favorable to avoid core formation. Average dislocation density was 4x10(3)/cm(2), which was comparable to that of Bi12SiO20 crystals grown by the Czochralski method. (C) 1999 Elsevier Science B.V. All rights reserved.