Domain-wall and reverse-domain superconducting states of a Pb thin-film bridge on a ferromagnetic BaFe12O19single crystal

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.