Anomalous Long-Range Proximity Effect in Template-Fabricated Single-Crystal Superconducting Nanowires

We report an anomalous proximity effect observed in single-crystal nanowires of Zn, Sn, and Pb of length up to 60 $\mu $m. These nanowires were electrochemically deposited into the pores of anodic aluminum oxide membranes and polycarbonate membranes. Using an \textit{in situ} self-contacting method, single nanowires were electrically contacted on both ends to a pair of macroscopic film electrodes of Au, Sn, and Pb pre-fabricated on both surfaces of the membranes. We observed that superconductivity in the nanowires was strongly suppressed when Au electrodes were used. When superconducting electrodes with higher transition temperatures were used, the nanowires became superconducting at the transition temperatures of the electrodes. We will present measurements of the sample resistance and the $I-V$ characteristics at various temperatures and magnetic fields. Scanning electron microscopy and transmission electron microscopy analyses of the structure and the composition of the nanowires will also be presented.