Effect of vanadium substitution on the microstructural and superconducting properties of Tl2Ba2Ca2−xVxCu3Oy superconductors

In this study, effects of the vanadium substitution for Ca sites on the Tl-2223 superconductor have been studied. The samples with nominal composition Tl2Ba2Ca2−xVxCu3Oy (x=0.0, 0.1, 0.3, 0.5, 0.7) have been prepared by the solid-state reaction method. The obtained samples have been characterized by x-ray diffraction, scanning electron microscope and the superconductivity of these samples have been investigated by electrical resistivity. X-ray powder diffraction pattern showed that there are some impurity phases as well as Tl-1223 main phase. Although the critical temperature (Tc) has increased for the first two substitution values, for the last two substitution values Tc has decreased. Higher amounts of vanadium substitution have caused non-superconductor. As a result, low vanadium substitution for Ca sites improved the Tl-2223 superconducting properties.