Magnetic field of Josephson vortices outside superconductors

TL;DR

This paper analyzes the magnetic field distribution of Josephson vortices near the boundary of superconductors, revealing that they do not spread in the junction direction and providing data relevant for Scanning SQUID Microscopy.

Contribution

It demonstrates that Josephson vortices maintain their structure near the boundary and calculates the magnetic field distribution outside superconductors, aiding experimental detection.

Findings

Josephson vortices do not spread near the boundary at scale λ_J

Magnetic field distribution outside the superconductor is characterized

Results are useful for Scanning SQUID Microscopy

Abstract

We consider the structure of Josephson vortices approaching the junction boundary with vacuum in large area Josephson junctions with the Josephson length $\lambda_J$ large relative to the London penetration depth $\lambda_L$. Using the stability argument for one-dimentional solitons with respect to 2D perturbations, it is shown that on the scale $\lambda_J$ the Josephson vortices do not spread near the boundary in the direction of the junction. %, which is in a striking difference with behavior of Abrikosov vortices exiting superconductors. The field distribution in vacuum due to the Josephson vortex is evaluated, the information needed for the Scanning SQUID Microscopy.