Nucleation and growth of superconducting phase in Bi2Sr2Ca2.2Cu3OX

The nucleation and growth of a superconducting phase were investigated using ball milled Bi2Sr2Ca2.2Cu3OX precursor powders. As the heat-treatment time increased, more Bi2Sr2Ca1Cu2OX (Bi-2212) changed to Bi2Sr2Ca2Cu3OX (Bi-2223) and the major second phase was changed from (Sr,Ca)14Cu24OX (14:24) to (Sr,Ca)2Cu1OX. Following the formation of the Bi-2212 phase near the 14:24 phase, the Bi-2223 phase nucleated preferentially at the interface between the Bi-2212 and 14:24 phases in the relatively short time of 20 h. The preferential nucleation of Bi-2223 was explained by its structural similarity and low interfacial energy with both the Bi-free and Bi-2212 phases. The texturing mechanism of Bi-2223 was discussed on the basis of its nucleation behavior