Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Superconductivity: Poster Session

TT 21.13: Poster

Montag, 16. März 2015, 15:00–18:00, Poster B

Observation of the Josephson effect on Ba-122 iron pnictide single crystals — •Noor Hasan¹, Stefan Schmidt¹, Sebastian Döring¹, Volker Tympel¹, Frank Schmidl¹, Paul Seidel¹, and Thomas Wolf² — ¹Friedrich-Schiller- Universität Jena , Institut für Festkörperphysik , Helmholtzweg 5, 07743 Jena, Germany — ²Karlsruhe Institute of Technology, Institut für Festkörperphysik , Hermann-von- Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

Since the discovery of the first Fe-based superconductors in 2006, extensive effort has been directed characterizing and modeling the novel properties of these exotic materials. Therefore Josephson junction offer ways to investigate the fundamental properties of iron pnictides. We use Ba(Fe_1−xCo_x)₂As₂ single crystals, prepared by a self-flux method , with an optimal Co concentration of 0.065 (critical temperature T_c=23.5K) . We realize Josephson junctions along the c-axis. To prepare them a newly developed surface polishing as well as standard thin film technologies are used. The artificial barrier consists of thin sputtered layers of various materials, normal conductors as well as insulators. A thermally evaporated double layer film of Pb and In was used as the counter electrode. For the characterization of the Josephson effect we will present temperature dependent I-V characteristics as well as I_c R_n − T dependencies and measurements under microwave radiation, including. Additionally results from tunneling and Andreev spectroscopy i.e temperature dependent dI/dV - V spectra are shown.