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TT: Fachverband Tiefe Temperaturen
TT 34: SC: Iron-Based Superconductors - 122
TT 34.9: Talk
Thursday, March 25, 2010, 16:15–16:30, H20
Calorimetric studies of hole-doped Ba0.68K0.32Fe2As2 multiband superconductor — •P. Popovich, A. V. Boris, O. V. Dolgov, D. L. Sun, C. T Lin, R. K. Kremer, and B. Keimer — Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
We report on the determination of the low temperature specific heat of hole-doped Ba0.68K0.32Fe2As2 single crystals with a sharp ( < 0.6 K) anomaly at Tc ≈ 38.5 K. The jump at Tc is ΔC/T ≈ 120 mJ/molK2. The low residual electronic specific heat ( < 2 mJ/molK2) shows that the amount of the non-superconducting impurities in our single-phase samples is less than 3%. In order to investigate the electronic part of the specific heat we subtracted a phonon background. As a background we used either our experimental specific heat data on a non-superconducting non-magnetic isostructural substance or a set of Einstein modes. Both models give qualitatively the same result. The α-model with two superconducting gaps fits well to the SC-induced electronic specific heat. Our findings imply that the superconducting properties of Ba0.68K0.32Fe2As2 can be well described in a framework of the strong-coupling model.