DIRECTIONAL SOLIDIFICATION BY APPROPRIATE CHEMICALLY ACTIVE SINGLE-CRYSTAL SEED - AN ALTERNATIVE WAY OF GENERATING LARGE SUPERCONDUCTING 123-SINGLE-DOMAIN

A Dy2O3 single crystal has been used as a seed for the growth of isoth ermally melt-textured Dy-123 material. The nucleation-controlled step has been observed to be related to the heterogeneous nucleation of 211 particles at the surface of the dysprosium oxide single crystal. The subsequent growth mode seems to be controlled by a high concentration gradient of dysprosium in the liquid phase. This leads to a directiona l solidification process of the 123 phase. The size of the 211 particl es seems to decrease as the distance from the dysprosium oxide single crystal increases.