GROWTH SHAPE-ANALYSIS OF ROUND YBA2CU3O7-X SINGLE-CRYSTAL FABRICATED BY THE PULLING METHOD

We constructed an automatic crystal pulling system for YBa2Cu3O7-x(Y12 3) and made a round cornered single crystal by keeping its growth temp erature around its peritectic temperature. The size of the round shape crystal was 4 mm in diameter and 4 mm in length[1]. A seed crystal wa s remelted at its corner first, and after the rounded cornered crystal was grown. Along the vertical axis, the crystal corner became wavy. T he remelting process was explained by free energy difference between t he flat interface to the square one. Growth shapes of the round corner were explained by temperature dependent growth rate anisotropy.