SINGLE-CRYSTAL GROWTH OF SUBSTITUTED YTTRIUM IRON GARNETS Y3FE5-X(GA,AL)XO12 BY THE FLOATING ZONE METHOD

Single crystals of YIG (5-10 mm in diameter and 50-100 mm in length) substituted with up to 20 at % of gallium and aluminum for the iron were successfully grown by the traveling solvent float zone (TSFZ) technique using a halogen lamp image furnace. The range of optimum growth conditions was studied and established. The growth techniques for Ga- and Al-substituted YIG were found to be essentially identical. The substitutions of grown crystals were found to be quite uniform. The relationship between the growth conditions and the internal structures of the crystals was studied particularly in the case of gallium substitution. The etching experiment revealed finely stratified growth striations in the adequately grown crystals as well as cellular growth structures in those grown inadequately. The successful application of the TSFZ technique was demonstrated by the fact that the dislocation density in the core region of a grown YIGaG crystal was below 102 cm-2. © 1979.