Properties of Ag Doped Bi-Superconductors Prepared by Solid State and Sol-Gel Methods
Superconductive ceramics with nominal composition Bi3.2Pb0.8Sr4Ca5Cu7Ox were prepared by solid state synthesis with 10 wt% of nanopowdered silver and were compared with those prepared by sol-gel method. The "in situ" polymerization route with citric acid and ethylene glycol was used to enhance homogeneity of the reaction mixture. The quality of samples was characterized by X-ray analysis, scanning electronic microscopy and the measurement of porosity. The superconducting properties were investigated by the measurement of the temperature dependence of magnetic susceptibility and by current voltage characteristic. All samples have critical temperatures in the range from 109 to112 K. Addition of silver always increases the volume of Bi-2223 phase and critical current density of the samples. Sol-gel samples reveal lower porosity, higher bulk density and better connectivity of the grains, resulting in the further enhancement of critical current density.
P. VINCENZINI and A. RIGAMONTI
D. Sýkorová et al., "Properties of Ag Doped Bi-Superconductors Prepared by Solid State and Sol-Gel Methods", Advances in Science and Technology, Vol. 47, pp. 104-107, 2006