Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: SC: Tunnelling, Josephson Junctions

TT 31.9: Talk

Thursday, March 25, 2010, 11:45–12:00, H21

Non-linear current-voltage characteristics of NS-tunnel junctions prepared by focused ion beam induced deposition — •Dirk Klingenberger, Oleksandr Foyevtsov, Fabrizio Porrati, and Michael Huth — Physikalisches Institut, Goethe-Universität, Max-von-Laue-Str.1, 60438 Frankfurt am Main.

We used a focused Ga-ion beam and the precursor W(CO)6 --injected into a vacuum chamber nearby the focal area of the beam-- to create tungsten containing superconducting deposits with a critical temperature of about 5.2 K. The deposits were fabricated onto oxidized aluminum contacts pre-patterned by UV-photolithography. I-V- and V-dI/dV- measurements have been performed between 0.3 K and 6 K using a He3-cryostat. For selected beam energies used during deposition the samples show Josephson-junction like behaviour or tunneling of quasiparticles for temperatures below the superconducting transition of aluminum at about 2 K. In the temperature range between the superconducting transitions of the two electrodes Andreev-reflection was observed.