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Pb containing ruthenium-based superconducting cuprates Ru ( Sr 1.5 Ca 0.5) PbCu 2 O 8 ( Ru -1212 type) have been successfully synthesized through the sol–gel route. The optimum annealing temperature for the ruthenium-based cuprate superconductor was found to be 890°C. The crystal structure determined by X-ray powder diffraction method showed a single Ru -1212 type phase with tetragonal symmetry with lattice parameters a = b = 3.920 Å, and c = 11.76 Å. The Ru ( Sr 1.5 Ca 0.5) PbCu 2 O 8 material showed onset temperature, Tc -onset at 35 K and zero resistant temperature, Tc -zero at 20 K. Pb together with the partial substitution of Sr with Ca lowered the formation temperature of the Ru -1212 type phase.

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A sol-gel route based on tatrate/acetate was used to synthesize RuSr 2 (Gd 2−x Cex)-Cu 2 O 10−δ (x = 0.5 to 0.7) cuprate superconductors. A sample, with x = 0.6, was heated to 1050 • C in oxygen flow for 24 h, followed by cooling at a rate of 1 • C/min until it reached 100 • C. The sample showed a single Ru-1222 phase with tetragonal symmetry. The lattice parameters for the sample were a = b = 3.863Å and c = 28.57Å. The onset transition temperature was 59 K, and the zero-resistance temperature was 40 K.