A new two-step method has been developed to synthesize (Hg,Re)Ba2Ca2Cu3Oy with lower annealing temperatures as compared to conventional methods using a precursor which contains the (Hg,Re)Ba2CaCu2Oy phase. In the first step, high phase purity (Hg,Re)Ba2CaCu2Oy superconductors are prepared from commercially available Ba2CaCu2Ox precursors, HgO, and Re2O7. In the second step, the finely ground (Hg,Re)Ba2CaCu2Oy is mixed with Ca-Cu-O and HgO. This precursor mix is encapsulated in evacuated quartz tubes and annealed for 8 to 48 h between 750°C and 850 °C. The resulting samples have (Hg,Re)Ba2Ca2Cu3Oy as a majority phase and exhibit a critical temperature of 133 K as prepared. The superconducting grains are platelike and randomly oriented. The grain sizes depend on the annealing time and temperature and reaches up to 30 μm diameter and 5 μm thickness. Second phases are mainly unreacted Ba2CaCu2Ox and Ca-Hg-O.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering