Superconductivity in clathrate-type silver oxides: Ag6O8MX (M = cation, X = anion)

We have performed physical property measurements of clathrate-type silver oxide: Ag6O8AgNO3, having a face-centered cubic structure with a space group of Fm 3 ¯ m . We examined the temperature dependence of heat capacity, electrical resistivity and magnetic susceptibility measurements. We confirmed the superconducting state and estimated that the upper critical magnetic field: Hc2 was to be about 710 Oe by the electrical resistivity measurements under various magnetic fields.