Domain-wall and reverse-domain superconducting states of a Pb thin-film bridge on a ferromagnetic BaFe_{12}O_{19} single crystal

TL;DR

This study visualizes nonuniform superconducting states in a Pb thin film on a ferromagnetic crystal, revealing domain wall and reverse-domain superconductivity phenomena near the critical temperature through low-temperature scanning laser microscopy.

Contribution

It provides direct imaging of domain wall and reverse-domain superconductivity states in a Pb film on a ferromagnetic substrate, highlighting their evolution with temperature and external magnetic field.

Findings

Visualization of domain wall superconductivity (DWS) near the critical temperature.

Observation of transition from DWS to reverse domain superconductivity.

Temperature and magnetic field dependence of superconducting states.

Abstract

We report on imaging of the nonuniform superconducting states in a Pb thin film bridge on top of a ferromagnetic BaFe_{12}O_{19} single crystal with a single straight domain wall along the center of the bridge by low-temperature scanning laser microscopy. We have visualized domain wall superconductivity (DWS) close to the critical temperature of Pb, when the Pb film above the domain wall acts as a superconducting path for the current. The evolution of the DWS signal with temperature and the external-field-driven transition from DWS to reverse domain superconductivity was visualized.