PREPARATION OF SUPERCONDUCTING YBA2CU4O8 BY THE SOL-GEL METHOD

Superconducting YBa2Cu4O8 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. YBa2Cu4O8 powder was obtained as a single phase by heating the gel at 780-degrees-C for 30 h in flowing oxygen. T(c) was 80 K from magnetic susceptibility measurements. Pelletizing and sintering this powder revealed T(c) (onset) of 87 K and T(c) (end) of 78 K from resistance measurements. YBa2Cu4O8 pellets sintered at 780-degrees-C for 30 h in O2 also consist of a single phase with T(c) (onset) of 85 K and T(c) (end) of 75 K.