Improved Method for the Growth of Yttrium-Iron and Yttrium-Gallium Garnets

Large single crystals of yttrium and rare earth iron garnets, and yttrium and rare earth gallium garnets, have been grown from molten solutions of lead oxide and lead fluoride. The crystals are grown by slowly cooling melts from about 1260°C to near 950°C. Sample compositions are: for YIG, 8 mole % ${\mathrm{Y}}_2{\mathrm{O}}_3$ , 22 mole % ${\mathrm{Fe}}_2{\mathrm{O}}_3$ , 30 mole % PbO and 40 mole % ${\mathrm{PbF}}_2$ ; for YGaG, 5.8 mole % ${\mathrm{Y}}_2{\mathrm{O}}_3$ , 14 mole % ${\mathrm{Ga}}_2{\mathrm{O}}_3$ , 39.4 mole % PbO and 40.8 mole % ${\mathrm{PbF}}_2$ . This method provides crystals both large in size and of superior quality. Best results are obtained when the containing crucible is hotter near its top than at its base since nucleation is thereby reduced.