Fabrication and Characterization of PbIn-Au-PbIn Superconducting Junctions

TL;DR

This paper reports on the fabrication and characterization of PbIn-Au-PbIn superconductor-normal metal-superconductor junctions, demonstrating their superconducting properties and potential for simple SQUID devices at relatively higher temperatures.

Contribution

It introduces a straightforward fabrication method for PbIn-Au-PbIn SNS junctions and demonstrates their superconducting behavior and SQUID functionality at accessible temperatures.

Findings

Maximum supercurrent of ~6 μA at 2.3 K

Supercurrent persists up to 4.7 K

Clear magnetic flux quantum oscillations in SQUID

Abstract

We report on the fabrication and measurement results of the electrical transport properties of superconductor-normal metal-superconductor (SNS) weak links, made of PbIn superconductor and Au metal. The maximum supercurrent reaches up to ~ 6 \mu A at T = 2.3 K and the supercurrent persists even at higher temperature of T = 4.7 K. Magnetic field dependence of the critical current is consistent with a theoretical fit using the narrow junction model. The superconducting quantum interference device (SQUID) was also fabricated using two PbIn-Au-PbIn junctions connected in parallel. Under perpendicular magnetic field, we clearly observed periodic oscillations of dV/dI with a period of magnetic flux quantum threading into the supercurrent loop of the SQUID. Our fabrication methods would provide an easy and simple way to explore the superconducting proximity effects without ultra-low-temperature cryostats.