Preparation of superconducting YBa2Cu408 by the sol-gel method

Superconducting YBa2Cu408 ceramics were synthesized by the sol-gel method using corresponding metal acetates as starting materials, water as solvent, and tartaric acid under 1 atm oxygen pressure. YBa2Cu408 powder was obtained as a single phase by heating the gel at 780 °C for 30 h in flowing oxygen. Tc was 80 K from magnetic susceptibility measurements. Pelletizing and sintering this powder revealed Tc (onset) of 87 K and Tc (end) of 78 K from resistance measurements. YBa2Cu408 pellets sintered at 780 °C for 30 h in O2 also consist of a single phase with Tc (onset) of 85 K and Tc (end) of 75 K.