Superconducting transition and Raman spectrum of Y1Ba2Cu3O7−x prepared by polymeric precursor synthesis

Abstract

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.

Modified Pechini Synthesis of Oxide Powders and Thin Films

“…After evaporation of the solvent, the gels were calcined and phase-pure YBCO was obtained at around 900 °C (Mazaki et al 1991). Sometimes BaCO3 could be detected after calcination at lower temperatures (Lee et al 1989). The resistivity of YBCO prepared with CA and EG is shown in Figure 7, demonstrating the superconducting transition.…”

“…The cation precursors used in modified Pechini syntheses for YBCO can either be nitrates or Y2O3 and CuO dissolved in HNO3 together with BaCO3 (Lee et al 1989). A possible precipitation of Ba(NO3)2 could be avoided by adding ammonia to adjust the pH to about 6 (Chu and Dunn 1987).…”

Modified Pechini Synthesis of Oxide Powders and Thin Films

“…The cation precursors used in modified Pechini syntheses for YBCO can either be nitrates (Kakihana et al 1991) or Y2O3 and CuO dissolved in HNO3 together with BaCO3 (Lee et al 1989). A possible precipitation of Ba(NO3)2 could be avoided by adding ammonia to adjust the pH to about 6 (Chu and Dunn 1987).…”