Preparation and substrate reactions of superconducting Y-Ba- Cu-O films.

Multiple metal-target d.c. magnetron sputter deposition of YBa sub 2 Cu sub 3 alloy in pure Ar followed by ex-situ oxygen annealing was used to prepare superconducting yttrium-barium- copper-oxide (YBaCuO) films on various substrates. Using Rutherford backscattering and Auger spectroscopies we examined film-substrate reactions which are degrading to superconductivity. Predeposited silver and niobium films as well as pre-reacted YBaCuO layers retard substate reactions; better superconductors were obtained with these buffer layers, particularly on cubic zirconia and magnesium oxide substrates.