Influences of thermodynamic factors on formation of RE1+xBa2-xCu3Oz superconductivity

REBa2Cu3O7-delta (RE123, RE = rare earth elements) has attracted much attention because of its potential application in developing electronic devices and coated conductors. Progress has been achieved in fabricating all kinds of RE123 superconductors and obtaining high-superconducting properties. In order to optimize the processing and gain the required performance, thermodynamic factors, such as oxygen partial pressure and composition of the solvent, related to crystal growth and superconductivity are discussed in this paper. It can be found that Y123 materials with good superconducting properties can be usually fabricated regardless of the composition of the solvent and the oxygen partial pressure, and a higher oxygen partial pressure means a higher growth rate. By carefully controlling on the composition of the solvent (or precursor) and the oxygen partial pressure, the grown Sm123 superconductors can exhibit the required performance. In contrast, the growth of Nd123 superconductors is less controllable relatively even in a low P(O-2) and Ba-rich solvents. (c) 2004 Elsevier B.V. All rights reserved.