Resistance anomaly near the superconducting transition temperature in short aluminum wires

We report a systematic experimental study of the superconducting resistive transition in one-dimensional Al wires of length 0.6 to 110 μm. Shorter wires show a peak in resistance as a function of temperature near ${\mathit{T}}_{\mathit{c}}$, with a value above the normal-state resistance. Near the peak, the resistance decreases sharply in a magnetic field of only a few Oe. In the same regime, the current-voltage characteristic resembles that of a superconductor-insulator-normal tunnel junction. These new results may be a manifestation of coherent effects in small superconducting samples.