Effect of CuO2 planes on the structural and superconducting transport properties of [CuTl − 12(n − 1)n;n = 2,3,4] superconductor family

Abstract

[Formula: see text] [Formula: see text] superconducting bulk samples have been synthesized by using two-step solid state reaction method. We investigated the effects of [Formula: see text] planes on the structural and superconducting transport properties of [Formula: see text] superconducting family. These samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) absorption spectroscopy and DC-resistivity [Formula: see text] measurements. These samples are [Formula: see text]-axis length oriented and have shown orthorhombic crystal structure. All the samples have shown metallic variations of resistivity from room temperature down to onset of superconductivity. The zero resistivity critical temperature [Formula: see text] increases with the increase in superconducting planes and normal state resistivity systematically decreases, which show the density of inadvertent defects decreases in the final compound. The apical oxygen phonon modes are hardened as observed in the FTIR absorption measurements. The intrinsic microscopic superconducting parameters, such as the cross-over temperatures, coherence length along [Formula: see text]-axis [Formula: see text] at 0 K, inter-layer coupling [Formula: see text], inter-grain coupling [Formula: see text] and fermi velocity [Formula: see text], were extracted from the fluctuation-induced conductivity (FIC) analysis. FIC analysis also showed the improvement in superconductivity with the increase in [Formula: see text] planes.