Magnetically induced anisotropy of flux penetration into strong-pinning superconductor/ferromagnet bilayers

We 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.

Keywords

ferromagnet, superconductivity, superconductor/ferromagnet bilayer, thin film, XMCD, Anisotropy, Aspect ratio, Barium compounds, Copper compounds, Ferromagnetic materials, Ferromagnetism, Iron alloys, Magnets, Nickel alloys, Niobium compounds, Superconductivity, Tantalum compounds, Thin films, Vortex flow, Yttrium barium copper oxides, Ferromagnets, Isotropic property, Magnetic stray fields, Scanning transmission x ray microscopy, Shielding currents, Small aspect ratio, Superconductor/ferromagnet bilayer, XMCD, Superconducting materials

URI

https://doi.org/10.34657/3627
https://oa.tib.eu/renate/handle/123456789/4998

Citation

Simmendinger, J., Hanisch, J., Bihler, M., Ionescu, A. M., Weigand, M., Sieger, M., et al. (2019). Magnetically induced anisotropy of flux penetration into strong-pinning superconductor/ferromagnet bilayers. 21(11). https://doi.org//10.1088/1367-2630/ab4f56

Collections

Physik

License

CC BY 3.0 Unported

https://creativecommons.org/licenses/by/3.0/

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