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Growth spirals of gadolinium gallium garnet (GGG) crystals

1981; Wiley; Volume: 16; Issue: 9 Linguagem: Inglês

10.1002/crat.19810160905

0023-4753

P. Naumowicz, K. Wieteska, S. Szarras, J. Cinak,

High-pressure geophysics and materials

Abstract Slices cut from various locations in two GGG spirals grown by the Czochralski method have been studied using double crystal X‐ray topography. In selected regions of the slices the lattice parameter has been measured by a modified Bond method. An increase of lattice parameter has been found in the outer part of the crystal where growth bands have smaller periodicity than those in the central region of the spiral. An analysis of crystallization front changes allowed us to suppose that the asymmetry of the heat field around the growing crystal, and the forced convection of the melt, are responsible for the crystal's growing in the shape of a spiral.