Vortex shells in mesoscopic triangles of amorphous superconducting thin films

TL;DR

This paper presents direct imaging of vortex arrangements in mesoscopic triangular amorphous superconducting films, revealing both commensurate and incommensurate patterns and analyzing vortex shell structures.

Contribution

It provides the first direct observation of vortex states in mesoscopic triangular superconducting dots and details their shell configurations and incommensurate patterns.

Findings

Vortices form triangular clusters and unique incommensurate patterns.

Vortex shells are identified and their packing sequences are constructed.

Distinct vortex arrangements depend on the applied magnetic field.

Abstract

Direct observation of vortex states confined in mesoscopic regular triangle dots of amorphous MoGe thin films was made with a scanning superconducting quantum interference device microscope. The observed magnetic images illustrate clearly how vortices are distributed over the triangle dots by forming not only commensurate triangular clusters, but also unique patterns imposed by incommensurability. We discuss the results in terms of vortex shells and construct the packing sequence of vortices in the multiple shell structure.