Micromagnet-superconducting hybrid structures with directional current flow dependence for persistent current switching

This letter reports on a microfabricated magnet-superconducting hybrid structure ( Co - SiO 2 - Pb 82 Bi 18 ) showing the dependence of the critical current ( I c ) on the current flow direction. With external magnetic field, intermittent superconducting and normally conducting regions are formed on the Pb 82 Bi 18 film due to field localization created by the Co stripes, which is verified by scanning Hall probe microscopy measurements. Superconducting and normal conduction paths are created parallel and perpendicular to the Co stripes, providing directional dependency on the current flow. By changing the orientation of the ferromagnetic stripes with respect to the superconducting film, the hybrid structure could be adapted to realize a low-power persistent current switch.