New family of copper-oxide-based isotropic metallic oxides for normalmetal barriers in SNS junctions,

摘要

Abstract: Thin films and heterostructures of a new family of copper- oxide-based isotropic metallic oxides such as La$-6.4$/Sr$- 1.6$/Cu$-8$/O$-20$/, La$-5$/BaCu$-6$/O$-13$/ and La$- 6$/BaYCu$-8$/O$-20$/ have been investigated. These metallic oxides are oxygen deficient pseudo-cubic perovskites that exhibits Pauli paramagnetism, which could be ideal normal metals for SNS junctions in high T$-c$/ superconducting devices. We have grown epitaxial thin films of these metallic oxides and SNS superconducting heterostructures in situ by 90 degrees off-axis sputtering. X-ray diffraction and cross-sectional transmission electron microscopy reveal these heterostructures to have high crystalline quality and clean interfaces. This material will facilitate fabrication of ideal SNS Josephson junctions with low boundary resistance due to its excellent chemical compatibility and lattice match with cuprate superconductors and will be useful for determining the source of interface resistance in such heterostructures. !25