Two superconducting transitions and periodic magnetoresistance oscillations in the crystalline Au nanowire with superconducting electrodes*

Transport measurements were made on individual crystalline Au nanowire with four focused ion beam (FIB) deposited tungsten (W) electrodes, which are superconducting below 5 K. It was found that the 1.2 microns long (between the inner edges of the two voltage electrodes) Au nanowire is superconducting. Instead of a single sharp drop to zero resistance as seen in usual superconductors, here the resistance drops in two steps. Below TC, with a magnetic field applied perpendicular to the axis of the nanowire, we found ``magnetoresistance mini-gaps'' in low field regime. In addition, clear periodic magnetoresistance oscillations in the superconducting to normal transition region were observed. The 1 micron and 1.9 microns Au nanowires were also investigated to further reveal the anomalous superconductivity we found.