Enhanced critical current density in Gd-added (Bi, Pb)-2212 bulk superconductor
Abstract:The effects of Gd addition on the phase evolution and superconducting properties of (Bi, Pb)-2212 prepared in the bulk polycrystalline form were studied. The Gd content in the samples was varied from 0.0 to 0.5 on a general stoichiometry of Bi1.7Pb0.4Sr2.0Ca1.1Cu2.1GdxOy. Phase analysis by means of x-ray diffraction, microstructural examination by scanning electron microscopy and superconducting property studies were carried out to evaluate the relative performances of the samples. It is observed that Gd addition enhances the transition temperature (TC) and critical current density (JC) of the system. Moreover no secondary phase containing Gd ions or any other cations was observed after the final stage of heat treatment. Microstructural examination shows clear and distinct morphologies for the Gd-added samples, wherein the grain growth is suppressed by the addition of Gd and the edges of the grains become more and more rounded. As a result, there is an increase in the porosity of the Gd-added samples, leading to a reduction in the sintered density for these samples.
Document Type: Research Article
Publication date: November 1, 2005