$\delta$-biased Josephson tunnel junctions

TL;DR

This paper studies the effects of a centrally fed bias current in long Josephson tunnel junctions, revealing how fractional vortices influence their behavior, supported by analytical, numerical, and experimental results.

Contribution

It introduces a detailed analysis of $$-biased Josephson junctions, highlighting the role of fractional vortices and providing experimental validation.

Findings

Fractional vortices significantly alter junction dynamics.

Analytical and numerical models match experimental data.

$$-biased junctions exhibit unique behaviors compared to uniform bias cases.

Abstract

The behavior of a long Josephson tunnel junction drastically depends on the distribution of the dc bias current. We investigate the case in which the bias current is fed in the central point of a one-dimensional junction. Such junction configuration has been recently used to detect the persistent currents circulating in a superconducting loop. Analytical and numerical results indicate that the presence of fractional vortices leads to remarkable differences from the conventional case of uniformly distributed dc bias current. The theoretical findings are supported by detailed measurements on a number of $\delta$-biased samples having different electrical and geometrical parameters.