Nucleation and Collapse of the Superconducting Phase in Type-I Superconducting Films

TL;DR

This paper investigates the phase transition dynamics in type-I superconducting films, revealing magnetic and topological hysteresis linked to domain shape changes and long-range magnetic interactions.

Contribution

It provides new insights into the nucleation and collapse processes of superconducting domains, highlighting the role of topological hysteresis and domain-shape instability.

Findings

Magnetic hysteresis with different transition fields for nucleation and collapse.

Observation of topological hysteresis involving domain shape changes.

Connection of hysteresis phenomena to long-range magnetic interactions.

Abstract

The phase transition between the intermediate and normal states in type-I superconducting films is investigated using magneto-optical imaging. Magnetic hysteresis with different transition fields for collapse and nucleation of superconducting domains is found. This is accompanied by topological hysteresis characterized by the collapse of circular domains and the appearance of lamellar domains. Magnetic hysteresis is shown to arise from supercooled and superheated states. Domain-shape instability resulting from long-range magnetic interaction accounts well for topological hysteresis. Connection with similar effects in systems with long-range magnetic interactions is emphasized.