THE BISMUTH INFLUENCE ON THE FORMATION OF HG-1234 PHASE

Partial substitution of mercury atoms by bismuth and its influence on the structural, superconducting and magnetic properties of the Hg-base d oxide superconductors have been investigated. Two series of samples of the nominal compositions Hg1-xBixBa2Ca2Cu3O8+delta and Hg1-xBixBa2C a3Cu4O10+delta, 0 less than or equal to x less than or equal to 0.5, h ave been prepared by the solid state reactions at normal pressure, by using the sealed quartz tube technique. For the bismuth content range of 0.2 less than or equal to x less than or equal to 0.25, for the fir st series and 0.1 less than or equal to x less than or equal to 0.20 f or the second one, the formation of the Hg-1234 phase in a high volume percentage, with the superconducting transition T-c(onset) similar to 130 K has been found. The X-ray powder diffraction data and the AC ma gnetic susceptibility measurements have been correlated. (C) 1997 Acad emic Press Limited.