GROWTH-RATE ANISOTROPY OF YBA2CU3O7-X SINGLE-CRYSTALS IN THE PULLING METHOD

The crystal growth rate anisotropy of YBa2Cu3O7-x (Y123) in the modifi ed pulling method was investigated by using Y123 single crystal seeds. The growth rate of {001} faces appeared on the side of the crystal gr own along [100] direction (R(ch)) was higher than that of {100} faces appeared on the side (R(ah)), at least in our experimental crystal gro wth condition, The growth rate ratio could be estimated as R(ch)/R(ah) = 1.3. This growth rate anisotropy, R(a) < R(c), seems to be attribut ed to the low supersaturation in the modified pulling method. The crys tal growth rate for both faces was proportional to the square of the s olute supersaturation, Several spiral patterns could be observed on (0 01) faces, while no spiral pattern could be observed on (100) faces, T his difference in the surface morphology indicates the difference of t he growth modes for both faces, and it might lead to the growth rate a nisotropy.