Synthesis and Characterization of Thallium Containing Bismuth Based Superconducting Materials

摘要

Bismuth based superconducting materials doped with thallium having a general formula Bi_(2-x)Tl_xPb_(0.4)Sr2Ca2Cu3O_y (x = 0.00, 0.05, 0.15, 0.25 and 0.35) were synthesized by the simple solid state reaction method. The effect of doping of thallium at the Bi-site, on the microstructure, electric and magnetic properties has been investigated through resistivity-temperature data, ac magnetic susceptibility and X-ray diffraction (XRD) analysis. It has been observed that the sample with thallium content, x = 0.25 has minimum room temperature resistivity value of 0.012 (ohm-cm) amongst all the samples studied here. The samples with x = 0.25 and 0.35 both have shown the highest Tc_(0) -109 K which is 4 K higher than that of the undoped sample. All of the samples were found to consist of both high-Tc (2223) and low-Tc (2212) phases in different proportions.