Epitaxial Sr/sub 2/RuO/sub 4/ heterostructures

Sr/sub 2/RuO/sub 4/ is the only known layered perovskite that is free of copper, yet superconducting. Its low metallic resistivity and excellent lattice match with YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// make it an attractive candidate for use as conductive electrodes to YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//-based superconducting devices or as a normal metal in YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//-based SNS junctions. We have determined optimal deposition conditions for growth of single-domain epitaxial films of Sr/sub 2/RuO/sub 4/. Films with excellent crystallinity are readily grown at substrate temperatures exceeding 1000/spl deg/C at low pressures. At lower temperatures and higher pressures, films predominantly consist of the SrRuO/sub 3/ phase. Resistivity versus temperature measurements reveal that the as-grown Sr/sub 2/RuO/sub 4/ films are metallic, but not superconducting. Epitaxial YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta///Sr/sub 2/RuO/sub 4/ heterostructures have also been grown. X-ray and resistivity measurements show that the YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films are of high quality.