• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.1-6
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• 1999

The microstructures of top seed mult processde $\textrm{YBa}_2\textrm{Cu}_3\textrm{O}_7$.$\delta$ single crystal were studied. Although shape of the seed was not faceted. the growth shape of Y123 single crystal was faceted. It was observed that Y211 phases were trapped in specific spaces of the faceted region. From the microstructural investigation. it was suggested that the segregation of Y211 is due to the difference of growth rates in crystal direction. When a single crystal was grown by the single seed with stepped multi surfaces. a microstrue was grown from multi-seed. The microstructure show the possibility of multi-seed growth. Corn kernel like structure without Y211 phase was observed and seemed to be formed by the diffusion reaction between Y211 phase in crystal and liquid wetted on the crystal. the diagonal line on Y123 crystal was observed that it was formed by the corn kernel like structure.