PREPARATION TECHNIQUES FOR GROWTH OF SINGLE CRYSTALS OF NONMETALLIC MATERIALS.
Final rept., 1 Jun 63-31 May 64,
GENERAL ELECTRIC CO SCHENECTADY N Y
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The report describes two techniques for growth of highpurity single crystals of nonmetallic materials using r-f induction-heating equipment in a frequency range of 5 to 100 Mc. One technique used for single-crystal growth was the Verneuil method using an induction-coupled plasma as a heat source instead of the conventional mixture of combustible gases. Materials that were melted in the plasma include Al2O3, CoAl2O4, NiO, Eu2O3-doped Y2O3, TiO2, CaO stabilized ZrO2, MgAl2O4, and MgO. Single crystals of CoAl2O4 were grown. The second crystal growth technique investigated was floating-zone melting using r-f induction heating. Materials that were directly r-f coupled and subsequently heated include NiO, TiO2, BaTiO3, CaO stabilized ZrO2, CoFe2O4, and yttrium iron garnet YIG. Molten zones were traversed through polycrystalline rods of CoFe2O4, YIG, and NiO with the majority of the work concentrated on NiO. The shape of the freezing liquidsolid interface appeared to be an important factor in crystal growth by this technique. Author