FORMATION OF THE "2223" SUPERCONDUCTING PHASE IN Bi4−xPbxSr3Ca3Cu4O16 SUPERCONDUCTORS

Formation of the "2223" superconducting phase in Pb doped Bi 4 Sr 3 Ca 3 Cu 4 O 16 superconductor is studied. The X-ray diffraction patterns of the Bi 4−x Pb x Sr 3 Ca 3 Cu 4 O 16 (0.7 < x < 1.2) superconductors formed by various heat treatments indicate that they are all multiphase systems containing both the high T c and low T c superconductors, with the volume fraction of the "2223" phase increasing with increased Pb content. The high temperature component have extrapolated T c 's of around 105 K. The zero resistivity temperature decrease with lead content but are well above the reported T c (75 K) of the Pb free host superconductor.