Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs
TT 17.5: Vortrag
Montag, 31. März 2014, 16:00–16:15, HSZ 201
Bicrystal Grain Boundary Junctions of P-doped and Co doped Ba-122 Thin Films — •Stefan Schmidt1, Sebastian Döring1, Frank Schmidl1, Volker Tympel1, Fritz Kurth2, Kazumasa Iida2, Bernhard Holzapfel2, Takahiko Kawaguchi3, Yasuhiro Mori3, Hiroshi Ikuta3, and Paul Seidel1 — 1Friedrich-Schiller-University Jena, Institute of Solid State Physics, Jena, Germany — 2IFW Dresden, Institute for Metallic Materials, Dresden, Germany — 3Nagoya University, Department of Crystalline Materials Science, Nagoya, Japan
We prepared grain boundary (GB) junctions of BaFe2(As0.66P0.34)2 thin films on bicrystal [001]-tilt LSAT and MgO substrates with GB angles of θ = 45∘. The junctions show clear Josephson effects and distinct Shapiro steps under microwave irradiation. Electrical characterization shows symmetric I-V characteristics which can be described with a combination of flux-flow behavior and the resistively shunted junction (RSJ) model. A large excess current Iex is observed. Their formal ICRN product is up to 50 µV at 4.2 K, which is decreased to 11 µV when taking Iex into account. Additionally, measurements on GB junctions of Fe-buffered Ba(Fe0.9Co0.1)2As2 thin films on STO bicrystal substrates (θ = 30∘) are shown for comparison. Their asymmetric RSJ behavior exhibits a formal ICRN product of 20 µV, whereas the excess corrected value is 6.5 µV.
This work was partially supported by DFG under project no. SE 664/15-1, the EU under project no. FP7-283141 (IRON-SEA), and the Landesgraduiertenförderung Thüringen.