RELATIONSHIP BETWEEN GROWTH-RATE AND UNDERCOOLING IN PT-ADDED Y1BA2CU3O7-X

Y1Ba2Cu3O7-x (Y123) crystals were grown by two different methods, the constant undercooling solidification and the continual cooling method, with top seeding by Sm123 seed crystals in order to investigate a rel ationship between undercooling (Delta T) and a growth rate (R). The cr ystals of Y123 with a sharp faceted interface, which consisted of {100 } and {001} faces, grew epitaxially from the seed, It was found that t he growth rates of {100} face (Ra) and that of {100} face (Rc) showed an increasing trend with increasing Delta T, and Rc was faster than Ra within these experimental conditions, Delta T < 20 K. The relation be tween R and Delta T follows the parabolic equation, viz. Ra proportion al to Delta T-1.9 and Rc proportional to Delta T-1.3 for {100} and {00 1} faces, respectively. The simulated crystal size using the R and Del ta T relations obtained from the constant undercooling method showed g ood agreement with experimental data by the continual cooling.