UHV compatible nanostructuring technique for mesoscopic hybrid devices: application to superconductor/ferromagnet Josephson contacts

We report on an ultra-high vacuum (UHV) compatible method for fabricating devices of sub-micrometer size by virtue of a non-organic evaporation mask of high thermal and mechanical stability. As an application we describe the superconducting properties of mesoscopic superconductor=normal-metal and superconductor=ferromagnet=superconductor hybrid structures. In particular, we report on the observation of the DC-Josephson e9ect in Nb=Cu=Co=Cu=Nbstructures prepared in UHV. The Josephson coupling between the two superconductors through the very thin (5 nm) magnetic and metallic weak link is con;rmed by the magnetic ;eld dependence of the critical current Ic, which displays a Fraunhofer-like interference pattern.