Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 64: Superconductivity: Heterostructures, Andreev Scattering, Vortex Physics
TT 64.7: Vortrag
Donnerstag, 14. März 2013, 16:45–17:00, H21
ac susceptibility investigation of vortex dynamics in nearly-optimally doped ReFeAsO1−xFx (Re = La, Ce, Sm) and Ba(Fe1−xCox)2As2 superconductors — •Giacomo Prando1, Romain Giraud1, Saicharan Aswartham1, Samuele Sanna2, Mahmoud Abdel-Hafiez1, Matteo Tropeano3, Hans-Joachim Grafe1, Marina Putti3, Sabine Wurmehl1, Anja Wolter-Giraud1, Bernd Buechner1, Roberto De Renzi4, and Pietro Carretta2 — 1Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, Germany — 2Dipartimento di Fisica, Universitá di Pavia and CNISM, Italy — 3Dipartimento di Fisica, Universitá di Genova, Italy — 4Dipartimento di Fisica, Universitá di Parma and CNISM, Italy
In this contribution we will report about the dynamical features of the flux lines in both optimally-doped ReFeAsO1−xFx and Ba(Fe1−xCox)2As2 superconductors as investigated by means of ac susceptometry. The features of pinning are derived in the case of ReFeAsO1−xFx powder samples for several Re ions within the framework of the thermally-activated flux-creep model. In the case of the investigated Ba(Fe1−xCox)2As2 single-crystal, the extremely high-quality and the associated low-degree of quenched disorder in the sample allow us to enlighten the emergence of a thermodynamical phase transition between the different configuration of vortices in the H − T phase diagram. Insights will be provided into the features of this phase transition and into the nature of the glassy phase, being turned into a Bragg-like glass at low values of magnetic field.