Author:
Greene L. H.,Feldmann W. L.,Barrier J. B.,Farrow L. A.,Miceli P. F.,Ramesh R.,Wilkens B. J.,Bagley B. G.,Giroud M.,Rowell J.M.
Abstract
AbstractSuperconducting thin films of YBa2Cu3O7 are prepared in-situ by on-axis, sputter deposition from a single, composite target. Our planar magnetron target composition of Y:Ba:Cu = 1.08:1.76:4.5 sputtered onto MgO at T~750°C in a 600mTorr Ar-O2 atmosphere yields reproducible superconducting films having Tc(R = 0)>80K and stoichiometry 1:2:3, that are shiny and of near epitaxial, crystalline quality. In order to ensure clean interfaces, YBa2Cu3O7/normal metal bilayers (to form SNS' Josephson junctions) and YBa2Cu3O7/normal metal/insulating barrier trilayers (to form SNIS' proximity tunnel junctions) are grown completely in-situ. (The S' = Pb counter electrode is evaporated ex-situ.) A supercurrent and Shapiro steps are observed in microwave irradiated SNS' (N = Ag) small area (5x10-5cm2) junctions. In SNIS' tunnel junctions, high-quality Pb tunneling is observed.
Publisher
Springer Science and Business Media LLC