Preparation of superconducting YBa2Cu3O/sub x/ thin films by oxygen annealing of multilayer metal films

Superconducting thin films consisting predominantly of YBa2Cu3O/sub x/ have been prepared by oxygen annealing of metal films formed by using electron beam evaporation to deposit a three-layer sequence of Cu, Ba, and Y in nominally stoichiometric proportions, then repeating the sequence five times. For the best superconducting films, which were prepared on yttria-stabilized cubic zirconia substrates, the onset of superconductivity occurred at 94 K and zero resistivity was observed at 72 K. For the best films prepared on sapphire substrates, the corresponding temperatures were 95 and 40 K