SUPERCONDUCTIVITY AT 112-117-K IN HGBA2CACU2O6+DELTA

The superconducting phase HgBa2CaCu2O6+delta With a sharp transition has been prepared and studied. Through studies of X-ray diffraction patterns, transmission electron microscopy, magnetization, and resistivity, we found that it has a tetragonal symmetry with lattice parameters a = 3.862 (1) angstrom and c= 12.707 (5) angstrom, with a main superconducting transition at approximately 112 K prior to oxygenation and approximately 117 K after prolonged oxygenation, and has a rather low irreversibility line. No superstructures of the type previously reported by Schilling et al. and Gao et al. in the > 130 K phase were detected in these samples.