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TT: Fachverband Tiefe Temperaturen

TT 29: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs 1

TT 29.11: Vortrag

Mittwoch, 28. März 2012, 18:00–18:15, H 2053

Transport measurements of lateral MgB₂/Fe/MgB₂ junctions — •Savio Fabretti, Patrick Thomas, Markus Schäfers, Oliver Schebaum, and Andy Thomas — Bielefeld University

We fabricated MgB₂/Fe/MgB₂ lateral junctions by rf-dc co-sputtering. The MgB₂ films have a thickness of about 30nm and a critical temperature of up to 33 K. The samples were annealed in-situ between 450^∘C and 750^∘C. Our MgB₂ films were sputtered on different substrates such as (100) MgO and r-cut sapphire . Their crystalline structure and magnetic anisotropy were investigated. For transport measurement a thin iron cross strip of about 30 nm was placed between the MgB₂ strip. The MgB₂ strip was relieved by a groove of about 5 µm. The superconductivity of MgB₂ is suppressed due to the proximity effect near the junction area and builds a natural metallic barrier. With this configuration, we get a magnetoresistance due to the domain wall scattering in iron where the magnetoresistance was measured perpendicular and in plane of this array. Further, we investigated their I-V and dI/dV characteristics in dependence of an applied magnetic field up to 4T. The sigma gap as well as the pi gap was observed.