Properties of the Nearly Free Electron Superconductor Ag5Pb2O6 Inferred   from Fermi Surface Measurements
  We measured the Fermi surface of the recently discovered superconductor Ag5Pb2O6 via a de Haas-van Alphen rotation study. Two frequency branches were observed and identified with the neck and belly orbits of a very simple, nearly free electron Fermi surface. We use the observed Fermi surface geometry to quantitatively deduce superconducting properties such as the in-plane and out-of-plane penetration depths, the coherence length in the clean limit, and the critical field; as well as normal state properties such as the specific heat and the resistivity anisotropy. 
P. D. A. Mann, M. Sutherland, C. Bergemann, S. Yonezawa, and Y. Maeno