STUDIES ON (HG,BI)-1212 - A 92 K SUPERCONDUCTOR

A series of (Hg, Bi)-1212 superconducting compounds has been synthesiz ed. The highest T-c the series (92 K) is found for the composition (Hg 0.67Bi0.33)Sr-2(Y0.5Ca0.5)CU2O7-delta, With lattice constants: a = 3.8 11 Angstrom, and c = 12.002 Angstrom. X-ray diffraction and SEM with E DX analysis confirm that Hg is indeed incorporated in the structure. H igh-pressure oxygenation at 250 bar and 400 degrees C changes the dema gnetization curve, adding a second transition at similar to 42 K; the 92 K transition remains unchanged. This behavior is explained in terms of phase segregation into oxygen ''rich'' and ''poor'' phases.