“…Bi-2212/x wt.%Ag and BSCO/x wt.%Ag (x = 1, 3, 5 and 10) precursors have been prepared from commercial Bi 2 O 3 (Panreac, 98 + %), SrCO 3 (Panreac, 98 + %), CaCO 3 (Panreac, 98.5 + %), CuO (Panreac, 98 + %), Co(NO 3 ) 2 • 6 H 2 O (Aldrich, ≥ 99 %) and Ag (Aldrich, 99.9 + %) powders by a sol-gel method via nitrates [18] to assure total cation solution, small particle size and good homogeneity in the initial mixture. The initial powders were suspended in distilled water, followed by dropwise addition of HNO 3 (Panreac, analysis grade) until a clear blue (for Bi-2212) or pink (for BSCO) solution was obtained.…”