Experimental investigation of flux motion in exponentially shaped Josephson junctions

TL;DR

This paper presents an experimental and numerical study of flux motion in exponentially shaped long Josephson junctions, revealing unique flux flow behavior and magnetic field asymmetry due to geometry-induced potential effects.

Contribution

It introduces the first detailed analysis of flux dynamics in exponentially shaped Josephson junctions, highlighting geometry-induced potential effects on flux motion.

Findings

Observation of quasi-linear flux flow branches

Asymmetric magnetic field response

Agreement between experimental data and numerical predictions

Abstract

We report experimental and numerical analysis of expontentially shaped long Josephson junctions with lateral current injection. Quasi-linear flux flow branches are observed in the current-voltage characteristic of the junctions in the absence of magnetic field. A strongly asymmetric response to an applied magnetic field is also exhibited by the junctions. Experimental data are found in agreement with numerical predictions and demonstrate the existence of a geometry-induced potential experienced by the flux quanta in nonuniform width junctions.