Fabrication of S-N-S Josephson junctions of Y-Ba-Cu-O/Au/Nb thin film sandwiches

The authors fabricated S-N-S (superconductor-normal-superconductor) Josephson junctions which consist of Y-Ba-Cu-O/Au/Nb thin-film sandwiches with various thicknesses of the Au barrier. Due to the AC-Josephson effect, Shapiro steps are observed in the S-N-S junctions under microwave radiation. The magnetic-field dependence of the critical current shows that the junctions behave as self-field-limited Josephson junctions. From the temperature dependence of the critical current near the transition temperature of the junctions, it is found that the thickness of the Au barrier is shorter than the coherence length of Au.<
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