Improvement of the high Tc phase and bond ordering in Bi–Sr–Ca–Cu–O superconductors by Pb doping

Abstract

High-T_c superconducting materials, (Bi_1−xPb_x)SrCaCuO with variable amount of lead (x = 0.01–0.12) were synthesized with various processing parameters and characterized by electron microprobe analysis (EPMA), X-ray diffraction, resistivity measurement and micro-Raman spectroscopy.

The Pb doping facilitates the formation of the Bi 2223 phase. The best high-T_c superconductivity is found with effective Pb amount around 12 percent, and ten days sintering.

Beyond 10% Pb, the doping was found to induce a Cu-O bond ordering in the direction parallel to the c axis.