The effect of simultaneous doping of Pb in Tl-Og layer of TlJ xPbxBa2Ca2Cu309-8 superconductors

In this paper we have reported investigations 011 the effect of simultaneous substitution of Pb at the Tl-based superconductor was prepared by adding an amount of Pb to the T.x PbxBa2Ca2Cu309-6 compound. The usual solid-state reaction method has been applied under optimum conditions. Bulk poiycrystalline samples have been prepared by the two-step solid state reaction process. It has been observed that the grown Tl|.xPbxBa2Ca2Cu;*CV$ (with x - 0.00, 0.10 , 0.20, 0.30 and 0.40) corresponds to the 1223 phase. The x-ray data of the sample showed a tetragonal structure with a high ratio of Tl-1223 superconducting phase. The samples showed a transition temperatures T « « w h i c h were 120 K. 123 K, 129 K, 131 , 134 K at (x = 0.0, 0.10, 0.20. 0.30 and 0.40) respectively. and the transition temperatures at zero resistance Tc(om were 101, 105, 108, 112 and 118 K, respectively. Resistivities were measured at different temperatures under zero magnetic fields and the data were interpreted. All the samples preparation with flow, we found that the O2 flow in our samples produced high- Phase superconductors. X-ray diffraction analysis showed an increase of the c-axis lattice constant for the samples doped with pb as compared with these have no pb content. It was found that the change of the pb concentrations of all our samples produced a change in the density pm, C/a and volume fraction Vph(i223).