Negative-resistance voltage-current characteristics of superconductor contact junctions for macro-scale applications

Voltage-current characteristics of mechanical pressure contact junctions between superconducting wires are investigated using a voltage-driving method. It is found that the switching regions at low voltages result from negative resistance of the contact junction. The current transport of the contact junctions is discussed from the perspective of two existing models: the multiple Andreev reflections at the two SN interfaces of a SNS (Superconductor/Normal metal/Superconductor) junction and the inhomogeneous multiple Josephson weak-link array.