Superconductivity in Au-Cr-Au and Ag-Pd-Ag Epitaxial Metal Film Sandwiches

摘要

Thin layers (1-2 nm) of Cr and Pd have been grown in Epitaxial Metal Film Sandwiches (EMFS) with Au or Ag, respectively. Half of the Au-Cr-Au samples and one Ag-Pd-Ag sample were superconductors. Cr grows in an fcc structure and Pd is in a stretched lattice, as was observed for Au-Pd-Au. Highest observed T/sub c/'s are 3.00 exp 0 K for Au-Cr-Au and 2.15 exp 0 K for Ag-Pd-Ag. All nonsuperconducting samples exhibit resistivity minima due to local moments. Large orbital contributions to H/sub c/ sub 2 are observed: 42 kOe/K for Au-Cr-Au and 71 kOe/K for Ag-Pd-Ag being measured with T/sub c/'s approx. = 1 K. These results agree with calculated values derived from the resistivities and a N(E/sub F/) for fcc Cr of 2.1 states/eV. The results are discussed relative to preliminary data for Au-V-Au and Ag-V-Ag EMFS. 8 figures. (ERA citation 08:023944)