Enhancement of supercurrent through ferromagnetic materials by interface engineering

Josephson junctions containing ferromagnetic materials exhibit interesting physics and show promise as circuit elements for superconducting logic memory. For memory applications, the properties of junction should be controllable by changing magnetic configuration inside junction. To achieve good switching properties, one choose a soft material such NiFe (permalloy); however, exhibits poor supercurrent transmission in junctions. In this paper, we put thin layers Ni on either side characterize behavior Ni/NiFe/Ni trilayers function thicknesses. Using thickness 0.4 nm, find that is not severely degraded relative to plain NiFe, while maximum $\ensuremath{\pi}$ state trilayer increased factor four We speculate enhancement due different spin-dependent transport Cu/Ni Cu/NiFe interfaces.