Oxygenation characteristics in high-density YBa2Cu3Ox ceramics

Oxygenation characteristics in high-density YBa2Cu3Ox ceramics with a relative sintered density ≥97%, which were produced by hot-pressing to have various oxygen contents as-hot-pressed, have been investigated. The results indicate that the oxygenation characteristic in the materials was strongly affected by their oxygen content before oxygenation; that is, the attainable oxygen content (directly connected with the superconducting temperature Tc) of the materials after oxygenation increases with a decrease in their oxygen content before oxygenation. Oxygen annealing at 500 degree C for 24 h dramatically increased the oxygen content of an YBa2Cu3Ox with x=6.08 before the oxygen annealing up to 6.90, while the oxygen content of an YBa2Cu3Ox ceramic with x=6.32 before oxygenation rose only to a value of 6.61 after the same oxygen annealing. This newly observed phenomenon on the oxygenation characteristic in the present materials may provide an idea for improving the superconducting properties in high-density YBa2Cu3Ox ceramics