Overdoped Samples Research Articles

Over-doped metallic behavior of Bi 2Sr 2CuO y: Synthesis of Bi-2201 with stoichiometric cation composition

We have newly synthesized a single phase of the Bi-2201 compound with stoichiometric cation composition under oxygen pressures of about 30 bar. This sample shows a metallic conductivity without any superconducting behavior down to liquid He temperature which is very similar to the over-doped sample of the isostructural Tl-2201 phase. Furthermore, it appears that the superconductivity of nonstoichiometric Bi 2+ x Sr 2- x CuO y ( x∼0.1) is not intrinsic from the results of AC susceptibility measurements.