title: Visualizing domain wall and reverse domain superconductivity.
abstract: In magnetically coupled, planar ferromagnet-superconductor (F/S) hybrid structures, magnetic domain walls can be used to spatially confine the superconductivity. In contrast to a superconductor in a uniform applied magnetic field, the nucleation of the superconducting order parameter in F/S structures is governed by the inhomogeneous magnetic field distribution. The interplay between the superconductivity localized at the domain walls and far from the walls leads to effects such as re-entrant superconductivity and reverse domain superconductivity with the critical temperature depending upon the location. Here we use scanning tunnelling spectroscopy to directly image the nucleation of superconductivity at the domain wall in F/S structures realized with Co-Pd multilayers and Pb thin films. Our results demonstrate that such F/S structures are attractive model systems that offer the possibility to control the strength and the location of the superconducting nucleus by applying an external magnetic field, potentially useful to guide vortices for computing application.
authors.affiliation: Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA.
authors.forename: M
authors.initials: M
authors.lastname: Iavarone
authors.affiliation: Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Moore
authors.affiliation: 1] Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA [2].
authors.forename: J
authors.initials: J
authors.lastname: Fedor
authors.affiliation: Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Ciocys
authors.affiliation: Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104, USA.
authors.forename: G
authors.initials: G
authors.lastname: Karapetrov
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: J
authors.initials: J
authors.lastname: Pearson
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: V
authors.initials: V
authors.lastname: Novosad
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Bader