Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 15: Superconductivity: Poster Session

TT 15.32: Poster

Dienstag, 26. Februar 2008, 14:00–18:00, Poster B

Tunneling transport properties in (La,Sr)₂CuO₄ grain boundary Josephson junctions — •Andreas Stöhr¹, Michael Wagenknecht¹, Dieter Koelle¹, Reinhold Kleiner¹, Gennady Logvenov², and Ivan Bozovic² — ¹Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany — ²Brookhaven National Laboratory, Upton, NY, U.S.A.

We investigate tunneling transport properties in thin film grain boundary Josephson junctions (GBJ‘s) of epitaxially grown (La,Sr)₂CuO₄ (LSCO) on bicrystal substrates. These optimally doped LSCO films were made by molecular beam epitaxy producing a very smooth film at the grain boundary. Measurements of the critical current I_c at low magnetic fields B (mT range) are used to characterize the quality of the junctions. Deviations from the ideal I_c(B) pattern enable us to indicate the homogeneity of the GBJ. Measurements of the differential conductance in high magnetic fields (T range) are used to investigate quasiparticle tunneling across the grain boundary. Results are compared to theoretical predictions.