Preparation and Magnetic Properties of Bi1.5Pb0.5Sr₂Ca₂Cu₃Ox Superconductors

New high- T c superconductors were prepared by the partial substitution of Pb for Bi in Bi 2 Sr 2 Ca 2 Cu 3 O x . The X-ray diffraction analysis of Bi 1.5 Pb 0.5 Sr 2 Ca 2 Cu 3 O x showed that most of the sintered sample was in the 105 K phase. The lattice parameters were a =5.410 Å and c =37.18 Å. The transition temperature was 105 K. The lower critical field, H c1 , was 6 Oe at 77 K which was much smaller than that of YBa 2 Cu 3 O 7- y (52 Oe). The volume fraction of the 105 K phase was estimated to be about 80%.