Investigation of the Crystal Shape Controllability of YBa 2 Cu 3 O 7-x Single Crystals in the Pulling Method

The influence of the geometrical difference on the crystal growth rate of YBa 2 Cu 3 O 7- x (Y123) single crystals in the modified pulling method was investigated. The growth rate of {001} faces appeared on the bottom of the crystals grown along direction ( R c v c ) was about 1.6–2.0 times higher than that of {100} faces appeared on the bottom of the crystals grown along direction ( R a v a ). R a v a is more sensitive to the change of supersaturation than R a h a (the crystal growth rate of {100} faces appeared on the side of the crystals grown along direction) for the low crystal pulling rate and for the low supersaturation regime, although these faces are crystallographically the same. These difference is attributed to the increase of the temperature at the crystal bottom face during the crystal growth. It is supposed from the experimental results that Y123 single crystals having long and nearly straight body parts with expanding about 25° can be obtained in the direction growth of the modified pulling method.