الفهرس | Only 14 pages are availabe for public view |
Abstract Study of effects of the chemical substitution on the physical properties of superconductor materials is of great importance to improve the superconducting properties. Many types of substitution have been performed in different high temperature superconductors and the results depend on the probable site occupancy. The replacement must be between ions of equivalent size. The substitution by the rare earth elements in high temperature superconductors has special interest for basic and applied physics. Usually, the rare earth elements substitute directly in the CuO2-plane itself, or indirectly through the substitution in the Ca-site are well known to alter the concentration of carriers occurs through the Cu-O network. This has a great importance for developing new superconducting materials conceived for diverse applications. In this work, the effect of partial substitution of Ca2+ and Cu2+ ions by Ho3+ and Sc3+ ions, respectively, on (Bi,Pb)-2223 phase has been studied. For this purpose, superconducting samples of types Bi1.8Pb0.4Sr2Ca2.1-x HoxCu3.1O10+δ phase with 0.000 ≤ x ≤ 0.200 and Bi1.8Pb0.4Sr2Ca2.1Cu3.1-xScxO10+δ phase with 0.000 ≤ x ≤ 0.175 were prepared using the standard solid-state reaction technique. The prepared samples were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) for phase analysis and microstructure examination, respectively. The elemental stoichiometric of the prepared samples was determined using energy dispersive X-ray (EDX). The X-ray data clarify that the partial substitution of Ca2+ and Cu2+ ions by Ho3+ and Sc3+ ions, respectively, does not influence the tetragonal structure of (Bi,Pb)-2223 phase. Moreover, X-ray analysis showed that the low Hocontent enhanced the phase formation up to x = 0.025 and for Sc-content up to x = 0.125. In addition, the surface morphology of the prepared samples displayed the decrease in the porosity among the grains, increased the microstructure density and grain size resulting in the improvement of inter-grain connectivity up to x =0.025 and x = 0.125 for Ho- and Sc-contents, respectively. On the other side, EDX results showed elemental contents very close to the starting values. |