Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 34: Superconductivity - Vortex Dynamics, Vortex Phases, Pinning

TT 34.4: Talk

Friday, March 30, 2007, 11:00–11:15, H19

Superconducting Transition Broadening in MgB₂ — •Anatolie Sidorenko¹, Vladimir Zdravkov¹, Andrej Sudru¹, Dimitriu Ghitsu¹, Thomas Koch², and Thomas Schimmel^2,3 — ¹Institute of Electronic Engineering and Industrial Technologies, ASM, MD-2028 Kishinev, Moldova — ²nstitute of Nanotechnology, Forschungszentrum Karlsruhe D-76021 Karlsruhe, Germany — ³Institute of Applied Physics, University of Karlsruhe D-76128 Karlsruhe, Germany

Superconducting properties of high-quality films of the first multiband superconductor, magnesium diboride, have been investigated. Two mechanisms with intrinsic origin of the superconducting transition broadening for MgB₂ were found. The dominating role of two-dimensional fluctuations in the vicinity of the critical temperature and thermally activated flux flow for the low parts of the superconducting transition are responsible for the resistivity of MgB₂ near the superconducting transition. The reasons for the observed extraordinary strong dependence of the activation energy of flux motion on the external magnetic field are discussed