The Deposition of Ceramic Superconductors

A Materials Science overview of the deposition of ceramic superconductors is presented. Whilst in the last four years the major effort has gone into the deposition of YBa2Cu3O7-∂ (YBCO), the bismuth and the thallium compounds will also be considered. The two major techniques of laser ablation and “off axis” sputtering will be discussed as well as evaporation, molecular beam epitaxy (MBE) and metallo-organic chemical vapour deposition (MOCVD). Emphasis will be placed on the in-situ deposition technique for YBCO though some consideration will be given to the “post heat treatment” methods being used for the bismuth and thallium compounds. One of the fundamental issues to be addressed will be the relationship between the deposition conditions and the properties of the films produced. The key issues of nucleation will be discussed, aiming at an understanding of the outstanding problems of preparing smooth uniform films.