Step Structure Observed in the Superconducting Transition of a Bulk Pb Wire with Very Low Current Densities

TL;DR

This study reports the observation of a hysteretic step structure in the superconducting transition of a bulk lead wire at very low current densities, providing new insights into dissipation mechanisms in the intermediate state.

Contribution

The paper presents experimental evidence of step structures in the superconducting transition of bulk lead, offering new observations that challenge existing models.

Findings

Hysteretic step structure observed in superconducting transition

Step structure is affected by current and magnetic field

Classical dissipation models provide partial interpretation

Abstract

We present measurements obtained on a bulk cylinder of lead with a SQUID picovoltmeter. A distinctive hysteretic step structure is observed. It is washed out on increasing the current and reinforced in higher field. Classical models for the dissipation mechanisms in the intermediate state are briefly reviewed and used to give a first interpretation of these results, although a complete understanding is not reached yet.