Origin of Hysteresis in a Proximity Josephson Junction

TL;DR

This paper reveals that hysteresis in S-N-S Josephson junctions at low temperatures is caused by electron temperature increases in the normal metal, driven by the thermal resistance of superconducting electrodes, based on direct temperature measurements.

Contribution

It provides direct experimental evidence linking hysteresis to electron heating and thermal resistance effects in Josephson junctions, clarifying the physical mechanism.

Findings

Hysteresis is due to electron temperature rise in the normal metal.

Thermal resistance of superconducting electrodes governs temperature increase.

Electron temperature increase correlates with resistive switching in the junction.

Abstract

We investigate hysteresis in the transport properties of Superconductor - Normal metal - Superconductor (S-N-S) junctions at low temperatures by measuring directly the electron temperature in the normal metal. Our results demonstrate unambiguously that the hysteresis results from an increase of the normal metal electron temperature once the junction switches to the resistive state. In our geometry, the electron temperature increase is governed by the thermal resistance of the superconducting electrodes of the junction.