Soft vortex matter in a type-I/type-II superconducting bilayer

TL;DR

This paper explores the complex and tunable magnetic flux patterns in a hybrid type-I/type-II superconductor bilayer, revealing novel vortex phases and transitions driven by various physical parameters.

Contribution

It demonstrates the hybridization of flux phases in a bilayer, leading to a variety of new vortex patterns and phases beyond traditional superconductor behavior.

Findings

Discovery of hybrid flux phases with unique vortex patterns

Identification of tunable transitions between different vortex arrangements

Observation of phases where flux domains influence vortex configurations

Abstract

Magnetic flux patterns are known to strongly differ in the intermediate state of type-I and type-II superconductors. Using a type-I/type-II bilayer we demonstrate hybridization of these flux phases into a plethora of unique new ones. Owing to a complicated multi-body interaction between individual fluxoids, many different intriguing patterns are possible under applied magnetic field, such as few-vortex clusters, vortex chains, mazes or labyrinthal structures resembling the phenomena readily encountered in soft matter physics. However, in our system the patterns are tunable by sample parameters, magnetic field, current and temperature, which reveals transitions from short-range clustering to long-range ordered phases such as parallel chains, gels, glasses and crystalline vortex lattices, or phases where lamellar type-I flux domains in one layer serve as a bedding potential for type-II vortices in the other - configurations clearly beyond the soft-matter analogy.