Excess Conductivity Analysis of Cu0.5Tl0.5Ba2Ca n−1Cu n O 2n+4−δ (n = 2, 3, 4) Thin Films

Abstract

Cu0.5Tl0.5Ba2Can−1CunO2n+4−δ (n = 2, 3, 4) thin film samples have been investigated for excess conductivity analysis (fluctuation-induced conductivity (FIC)). The thin films are c-axis oriented and have shown the tetragonal structure in which the Tc (R = 0) of the samples increases with an increasing number (n) of the CuO2 planes. The FIC analysis is carried out by following the Aslamazov-Larkin theory and in the critical regimes from the Ginzburg-Landau number. By employing the Ginzburg-Landau theory, we have calculated important superconductivity parameters. The values of ξc(0), VF, and τφ increase, but the inter-layer coupling (J) of CuO2 planes is suppressed with the increasing number of CuO2 planes in these samples. The λpd, however, is suppressed, but the values of Bc(T), Bc1(T), and Jc(0) increase with the increasing number of conducting planes in Cu0.5Tl0.5Ba2Can−1CunO2n+4−δ (n = 2, 3, 4) samples. This demonstrates the increase in flux pinning characters that is most likely induced by thallium defects in the charge reservoir layer.