Eur. Phys. J. Appl. Phys. 38, 47-51 (2007)
https://doi.org/10.1051/epjap:2007044

Absence of pair breaking effect in Cu_0.5Tl_0.5Ba₂Ca₂Cu_3−y Zn_yO_10−δ (y = 0, 0.75, 1.5, 2.25, 2.5, 2.65) superconductor

Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320, Pakistan

Received: 5 August 2006
Revised: 29 September 2006
Accepted: 26 January 2007
Published online: 22 February 2007

Abstract

We have investigated the existence of any possible pair breaking mechanism in Cu_0.5Tl_0.5Ba₂Ca₂Cu_0.35Zn_2.65O_10−δ superconductor by carrying out post-annealing experiments in nitrogen, oxygen and air atmospheres. This material is grown in tetragonal structure with a and c-axes lengths 3.879 Å and 14.581 Å; the c-axis length is found to decrease with the increased concentration of Zn in the final compound. The substitution of Zn at CuO₂ planar sites in formula unit Cu_0.5Tl_0.5Ba₂Ca₂Cu_3−yZn_yO_10−δ has given superconductivity for all the Zn doping concentration of y = 0.75, 1.5, 2.25, 2.5, 2.65. The zero resistivity critical temperature [T_c(R = 0)], the quantity of diamagnetism and critical current [I_c(H = 0)] are found to increase with increased Zn doping. In Zn doped samples, post-annealing in air has given a maximum increase in superconducting properties, which showed that final material is optimally doped with carriers in ZnO₂ planes. Since the superconducting properties are marginally suppressed in Zn doped samples by post annealing in O₂ and N₂ atmospheres, it has lead to a definite conclusion that pair breaking mechanism, suggested in previous studies, are absent altogether in our Cu_0.5Tl_0.5Ba₂Ca₂Cu_0.35Zn_2.65O_10−δ superconductor. The synthesis of Cu_0.5Tl_0.5Ba₂Ca₂Zn₃O_10−δ superconductor by this method is extremely reproducible.