Improvement the superconducting parameters of Tl-1212 by Ruthenium substitution

Abstract

Series of superconductor samples with a nominal composition of Tl1-xRuxBa2CaCu2O7-δ with 0 < x > 0.3 have been prepared via a solid-state reaction technique. The prepared samples have been characterized using x-ray powder diffraction (XRD) and scanning electron microscope (SEM). The tetragonal structure of Tl-1212 phase is not affected by Ruthenium-substitution whereas the lattice parameters a and c have been affected by this substitution. The electrical resistivity as well as the transport critical current density, for the prepared samples, is measured using a conventional four- probe technique. The superconducting transition temperature, Tc, enhances as x increases from 0 to 0.05 and then it decreases, indicating that the Ruthenium improves the Tc of Tl-1212 phase till x = 0.05. Also, the critical current, at 68 K without applied magnetic field, enhances from 75.23 A/cm2 for x = 0 to 182.6 A/cm2 for x = 0.05 and then it decreases to 35.21 A/cm2 for x = 0.15. The electrical resistivity measurements for the samples with x > 0.15 show an anomalous behavior at temperatures around 120-180K, indicating the localization effect and the disorder of cations and oxygen.