High phase purity (Hg,Re)Ba2Ca1Cu2Oy and (Hg,Re)Ba2Ca2Cu3Oy, superconductors were prepared from commercially available Ba2Can-1CunOx precursors, HgO, and Re2O7. The addition of Re was found to have beneficial effects on the phase formation and chemical stability of the superconducting materials. Optimal annealing temperatures were found to be above 880°C for the (Hg,Re)Ba2Ca2Cu3Oy phase and below 850°C for the (Hg,Re)Ba2Ca1Cu2Oy phase. The microstructure of the samples is dominated by high density island-like superconducting areas interconnected by low density superconducting material and second phases. The randomly oriented platelike superconducting grains are typically around 5 μm thick and up to 100 μm long. Investigations of (Hg,Re)Ba2Ca2Cu3Oy samples quenched from various annealing stages indicate that the (Hg,Re)Ba2Ca2Cu3Oy phase forms via the (Hg,Re)Ba2Ca1Cu2Oy phase and is assisted by a liquid phase on a microscopic length scale.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering