Abstract

Doping with combinations of Tl_0.3-xSn_x in a certain concentration range enhances the zero resistivity temperature Tc₍₀₎ from 104 to 108K. Both high-Tc (2223) and Low-Tc (2212) phases were detected by the X-ray diffraction analysis. However the low-Tc phase is found to dominate over the high-Tc phase with the increase in Sn content. Critical temperatures were determined by the electrical resistivity and ac magnetic susceptibility measurements. Amongst the doped samples studied here a sample containing Sn content of x = 0.06 exhibits comparatively the lowest value of ΔT = 5K, the lowest room temperature resistivity of ρ_RT = 0.01494 ohm-cm and the highest value of Tc₍₀₎ = 108K.

Key words: Bismuth based high-Tc superconductors, X-ray diffraction, resistivity, susceptibility