GROWTH OF MGGA2O4 CRYSTALS BY PBO-PBF2-B2O3 FLUX METHOD

An attempt to grow crystals of MgGa2O4 was made by slow cooling of PbO-PbF2-B2O3 flux with varying B2O3 amount, in which MgO and Ga2O3 were dissolved as solutes. The growth was conducted by heating mixtures at 1200, 1100 or 1000°C for 10 hours followed by cooling to 500°C at a rate of 5°C/hr. Results obtained were summarized as follows: (1) When the soaking temperature was 1200°C, the optimum composition of mixture to grow the crystal was MgO(12 mol%)-Ga2O3(8 mol%)-PbO(35 mol%)-PbF2(35 mol%)-B2O3(10 mol%). Crystals grown in PbO-PbF2 flux containing a proper quantity of B2O3 bigger, more colorless and more transparent than those grown in PbO-PbF2 flux. (2) When the optimum composition was used, a tendency for the crystal to grow bigger was increased as the soaking temperature was raised. (3) A maximum weight of the crystal grown in the mixture of 50 g in weight was about 168 mg (about 5 mm in size). The crystals were basically octahedral form with {111} faces, colorless and transparent. (4) A density of crystals, picnometrically determined, was 5. 32 g/cm3. This value was in good agreement with the one reported in a literature. © 1979, The Chemical Society of Japan. All rights reserved.