ON THE REPRODUCIBILITY OF THE RESISTIVE TRANSITION ANOMALIES IN SUPERCONDUCTING NANOSTRUCTURES

Four contact R(T) measurements have been performed for various multi-p robe aluminium nanostructures. For several samples (combinations of pr obes) the resistance at the top of superconducting transition can incr ease the corresponding normal state value. The effect is not fully rep roducible, being dependent upon cooling history and particular arrange ment of voltage and current probes. While the resistive transition, th e inevitably formed normal superconducting boundary is considered to b e responsible for the observed anomaly due to additional voltage step at the N/S interface. The absence of full reproducibility of experimen tal results is attributed to the dramatic sensitivity of mesoscopic-si ze samples transport properties on the variation of boundary (scatteri ng) conditions.