CRYSTAL-GROWTH AND CHARACTERIZATION OF GADOLINIUM GALLIUM GARNET

Single crystals of gadolinium gallium garnet with dislocation and inclusion levels below 5/cm**2 were grown in a nitrogen atmosphere with an infrared televison system of computer controlled Czochralski crystal growth. Coring was prevented by a high crystal rotation rate and a slow pull rate during growth, although striations occurred in the crystal at high rotation rates. Dislocations were avoided by good crysal diameter control during growth and low thermal gradients in the crystal puller. Etching and polishing techniques were developed to reveal defects.