Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 3: Superconductivity: Properties and Electronic Structure I
TT 3.6: Vortrag
Montag, 12. März 2018, 10:45–11:00, H 0110
Two-gap superconductivity in the AgxMo6S8 Chevrel Phase — •Manuel Feig1,2, Matej Bobnar2, Christoph Hennig3, Igor Veremchuk2, Andreas Leithe-Jasper2, and Roman Gumeniuk1,2 — 1Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany — 2Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany — 3European Synchrotron Radiation Facility, 71, Avenue des Martyrs, Grenoble, France
The Rietveld refinement of HR-PXRD data on the superconducting Ag0.92Mo6S8 confirmed the Chevrel-like structure: SG R3, a = 9.3065 Å and c = 10.8310 Å.
Magnetization measurements revealed a superconducting transition at Tc = 7.9 K. The lower and upper critical magnetic fields Bc1 = 12 mT and Bc2 = 3.5 T were deduced from the hysteresis. In contrast, measurements of the electrical resistivity in different magnetic fields resulted in Bc2 = 7.4 T as well as the GL-coherence length ξGL = 67 Å, the GL-parameter κ = 33 and the London penetration depth λL = 2204 Å. The specific heat jump at the superconducting transition Δ cp/γ Tc = 1.77 is well above the value predicted by BCS theory (1.43), whereas the energy gap ratio Δ(0)/kBTc = 1.55 obtained from an exponential fit of the electronic specific heat cel from 0.35 K to 4 K is smaller than the theoretically predicted value of 1.76. In agreement with the isostructural SnMo6S8 and PbMo6S8 Chevrel phases [1], Ag0.92Mo6S8 is a two-band superconductor with the gap ratios Δ1/kBTc = 2.39 (95%) and Δ2/kBTc = 1.03 (5%).
A.P. Petrović et al., Phys. Rev. Lett., 106, 017003 (2011)