Possible RT superconductivity from Pb3CO5-Ag2O (PACO) system

Some interesting results that could be eventually explained as coming from superconductivity (SC) in Pb3CO5-Ag2O (PACO) system are reported. Samples p repared at 340-350 degreesC in combined CO2-O-2 atmosphere exhibit low resi stance states at room temperature (RT) with resistivity three orders of mag nitude lower than that of silver. In addition, characteristic threshold cur rent density dependence of electric resistance together with the DC suscept ibility data obtained on balance support the idea of superconductivity in P ACO system.