CC BY 3.0 UnportedSimmendinger, J.Hanisch, J.Bihler, M.Ionescu, A.M.Weigand, M.Sieger, M.Hühne, R.Rijckaert, H.Van Driessche, I.Schütz, G.Albrecht, J.2020-07-182020-07-182019https://doi.org/10.34657/3627https://oa.tib.eu/renate/handle/123456789/4998We studied the impact of soft ferromagnetic permalloy (Py) on the shielding currents in a strong-pinning superconductor - YBa2Cu3O7-δ with Ba2Y(Nb/Ta)O6 nano-precipitates - by means of scanning transmission x-ray microscopy. Typically and in particular when in the thin film limit, superconductor/ferromagnet (SC/FM) bilayers exhibit isotropic properties of the flux line ensemble at all temperatures. However, in elements with small aspect ratio a significant anisotropy in flux penetration is observed. We explain this effect by local in-plane fields arising from anisotropic magnetic stray fields originated by the ferromagnet. This leads to direction-dependent motion of magnetic vortices inside the SC/FM bilayer. Our results demonstrate that small variations of the magnetic properties can have huge impact on the superconductor.enghttps://creativecommons.org/licenses/by/3.0/530ferromagnetsuperconductivitysuperconductor/ferromagnet bilayerthin filmXMCDAnisotropyAspect ratioBarium compoundsCopper compoundsFerromagnetic materialsFerromagnetismIron alloysMagnetsNickel alloysNiobium compoundsSuperconductivityTantalum compoundsThin filmsVortex flowYttrium barium copper oxidesFerromagnetsIsotropic propertyMagnetic stray fieldsScanning transmission x ray microscopyShielding currentsSmall aspect ratioSuperconductor/ferromagnet bilayerXMCDSuperconducting materialsArticle