PROBLEMS IN EPITAXIAL-GROWTH OF HIGH-TC SUPERCONDUCTORS

Complex cuprate compounds with high temperature superconductivity (HTSC), up to 125 K, have been discovered in the last 5 years. These cuprates could find numerous applications if their material and crystallization problems could be solved. In this paper, the epitaxy and substrate problems are discussed for YBa2Cu3O7 ("YBCO"), the best-known HTSC compound with T(c) almost-equal-to 92 K. Its limited thermal and chemical stability in combination with very short coherence lengths require a surface and interface control in the subnanometer range which has not been achieved with present epitaxial deposition techniques and available substrates.