Current-phase relation of the SNS junction in a superconducting loop

TL;DR

This paper investigates the current-phase relationship in SNS junctions within superconducting loops, explaining experimentally observed non-sinusoidal persistent currents at finite temperatures through theoretical analysis.

Contribution

It provides a theoretical framework for understanding the current-phase relation in SNS junctions, accounting for finite temperature effects and experimental observations.

Findings

Persistent currents are highly non-sinusoidal at finite temperatures.

Maxima of the current occur near zero external flux.

Theoretical results align with experimental data.

Abstract

We study the current-phase relation of the superconductor/normal/superconductor (SNS) junction imbedded in a superconducting loop. Considering the current conservation and free energy minimum conditions, we obtain the persistent currents of the normal/superconductor (NS) loop. At finite temperature we can explain the experimentally observed highly non-sinusoidal currents which have maxima near the zero external flux.