Mechanism for flux guidance by micrometric antidot arrays in superconducting films

TL;DR

This paper investigates how micrometric antidot arrays in superconducting films influence magnetic flux guidance and penetration, combining experimental magneto-optical imaging with advanced numerical simulations to understand flux behavior and current flow.

Contribution

It introduces a novel numerical scheme for simulating flux dynamics in complex antidot geometries, accurately reproducing experimental observations and providing detailed insights into flux and current distributions.

Findings

Strong flux guidance observed in antidot arrays

Numerical simulations match experimental flux patterns

Large electrical fields occur in narrow connecting channels

Abstract

A study of magnetic flux penetration in a superconducting film patterned with arrays of micron sized antidots (microholes) is reported. Magneto-optical imaging (MOI) of a YBCO film shaped as a long strip with perpendicular antidot arrays revealed both strong guidance of flux, and at the same time large perturbations of the overall flux penetration and flow of current. These results are compared with a numerical flux creep simulation of a thin superconductor with the same antidot pattern. To perform calculations on such a complex geometry, an efficient numerical scheme for handling the boundary conditions of the antidots and the nonlocal electrodynamics was developed. The simulations reproduce essentially all features of the MOI results. In addition, the numerical results give insight into all other key quantities, e.g., the electrical field, which becomes extremely large in the narrow channels connecting the antidots.