Current-voltage characteristics of Pb and Sn granular superconducting nanowires

Arrays of granular superconducting Pb and Sn nanowires (40 - 55 nm in diameter and 22 or 50 mum long) have been prepared by electrodeposition in nanoporous membranes. A simple technique has been developed to perform electrical transport measurement on a single nanowire. By sweeping the dc current inside the nanowire, we observed the formation of phase-slip-centers far below the critical temperature. In contrast, in voltage-driven experiments, an interesting S-shaped behavior has been observed in the nucleation region of these phase-slip-centers. (C) 2003 American Institute of Physics.