High-Tc superconducting Y1Ba2Cu3O7−x bulk samples were prepared by polymeric precursor synthesis. Resistance, x-ray diffraction, and Raman scattering measurements were performed for sample characterization. The bulk specimen exhibited a sharp superconducting transition at 94.5 K with a 10%–90% transition width of 0.5 K. Four Raman active phonon modes were observed at frequences of 150, 337, 440, and 502 cm−1 in the 120–700 cm−1 region.

Three samples of superconductors of the title system are prepared using the normal 1:2:3 ratio of Y2O3, BaCO3, and CuO, and additionally the ratios 0.8:2:3 and 1.1:2:2.8 to prepare specimen with and without a liquid phase.

Electrical and magnetic properties of the superconducting oxides with nominal composition (Bi0.7 Pb0.3 )2Sr2Ca2 Cu3 Ox prepared from polymeric precursors have been investigated. Superconducting transition with zero-resistance temperature at T=108 K was achieved for a sample sintered at 840 °C under a low oxygen pressure. The critical current density at 77 K in a zero magnetic field is ∼400 A/cm2 , which is much higher than that of the Pb-free sample. Variations of the superconducting transition temperature, the critical current density, and magnetic properties with heat treatment time are discussed in connection with the structural properties.