Dynamics of stripe patterns in type-I superconductors subject to a rotating field

TL;DR

This study investigates how stripe patterns in type-I superconductors evolve under a rotating magnetic field, revealing complex behaviors like co-rotation, zigzag instability, and segment reconnection influenced by pinning effects.

Contribution

It provides the first detailed experimental analysis of stripe pattern dynamics in type-I superconductors under rotating fields, highlighting the role of pinning and pattern reconnection.

Findings

Stripe patterns co-rotate with the field at small angles.

Large angles induce zigzag instability and stripe breaking.

Reconnection of segments into longer stripes occurs during rotation.

Abstract

The evolution of stripe patterns in type-I superconductors subject to a rotating in-plane magnetic field is investigated magneto-optically. The experimental results reveal a very rich and interesting behavior of the patterns. For small rotation angles, a small parallel displacement of the main part of the stripes and a co-rotation of their very ends is observed. For larger angles, small sideward protrusions develop, which then generate a zigzag instability, ultimately leading to a breaking of stripes into smaller segments. The short segments then start to co-rotate with the applied field although they lag behind by approximately $10^\circ$. Very interestingly, if the rotation is continued, also reconnection of segments into longer stripes takes place. These observations demonstrate the importance of pinning in type-I superconductors.