Possible Superconductivity in Ag5Pb2O6 Probed by AC Susceptibility

We will present the physical properties of a layered silver oxide Ag5Pb2O6. The resistivity shows T2 dependence in an unusually wide range of temperature, up to room temperature. Considering the specific heat, this T2 dependence is not attributable to either strong electron correlation or strong electron-optic phonon interaction. In the AC susceptibility measurements we found a diamagnetic phase transition around 48 mK, which suggest the superconductivity of Ag5Pb2O6. Positive peaks of the real part of the AC susceptibility, observed in magnetic fields, indicate reversibility of magnetic process. These observations implies that Ag5Pb2O6 is a type-I superconductor, which are quite rare among oxides.