Modulation of a Josephson current through an Nb/Al-AlOx/Nb Josephson junction by a parallel magnetic field and a perpendicular magnetic field

摘要

We have investigated the perpendicular magnetic field dependence of Josephson current through Nb/Al-AlOx/Nb junctions by applying a magnetic field in a direction perpendicular to the plane of the junction. We found hysteresis in the modulation characteristics of the Josephson current when a strong perpendicular magnetic field was applied to the Josephson junction. We have now measured the three-dimensional magnetic field dependence of the Josephson current by applying magnetic fields Hx and Hy in the direction parallel to the plane of the junction and magnetic field Hz in the direction perpendicular to the plane of the junction. When the perpendicular magnetic field Hz was applied to the Josephson junction, the main peak of the Fraunhofer pattern shifted from the origin of the (Hx and Hy) plane. We investigated why Josephson current is modulated by a perpendicular magnetic field Hz.