Synthesis and Characterization of Tl-1223 Substituted by Scandium

Abstract

X-ray powder diffraction, scanning electron microscopy (SEM), energy dispersive X-ray, electrical resistivity and AC-magnetic susceptibility measurements have been performed for polycrystalline superconducting samples of type TlBa 2 Ca 2− x Sc x Cu 3 O 9− δ (0.0 ≤ x ≤ 0.6). The powder X-ray diffractograms indicate that the tetragonal structure of Tl-1223 is not affected by Sc-substitution whereas the lattice parameters are changed. The X-ray analysis indicates that the low-contents of scandium ( x ) enhance the formation of Tl-1223 and reduce the secondary phases. The grain-size determined by SEM decreases as x increases. The electrical resistivity measurements show suppression in the superconducting transition temperature, T c , and an increase in both the residual resistivity and the superconducting transition width as x increases. The suppression in T c is attributed to the hole-filling mechanism.