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

摘要

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