Realistic Pearl vortices in thin film superconductors

TL;DR

This paper investigates magnetic field profiles of vortices in thin-film superconductors, revealing a universal magnetic field variation that depends on sample thickness and differs from classical exponential or power-law behaviors.

Contribution

It introduces a new understanding of vortex magnetic screening in thin films, showing a universal curve and quantifying the crossover from bulk to thin superconductor behavior.

Findings

Magnetic screening in thin films follows a universal curve scaled by thickness.

The magnetic field profile deviates from exponential and power-law predictions.

Different screening length-scales are identified for analyzing experimental data.

Abstract

We analyze magnetic field profiles of vortices in thin-film superconductors, shedding new light on this old and presumed settled problem. In sufficiently thin films with realistic Ginzburg-Landau parameter $\kappa = 1/\sqrt{2}$, the magnetic screening around a vortex core is neither exponential -- as is expected in bulk -- nor the power-law that was predicted by Pearl. Instead, a universal curve for the magnetic field variation appears that scales with the sample thickness. The thickness dependence is consistent with the seminal Pearl length, and serves as an indication of the reduced magnetic field screening present in two-dimensional superconductor. Finally, we quantify the crossover from bulk-like to thin superconductors, and establish different screening length-scales relevant for the analysis of experimental data.