Determination of oxygen non-stoichiometric fraction, δ, in single-phase superconducting YBa2Cu3Om+δ

The hydrogen/carbon mono-oxide reduction method, based on the difference in thermodynamic stability of yttrium oxide, barium oxide and copper oxide, has been used to determine the oxygen non-stoichiometric fraction, the δ value, in single-phase superconducting YBa 2 Cu 3 O 6.5+ δ . The δ value was found to +0.7 for samples produced by directed reaction process under the given conditions. The present authors regard YBa 2 Cu 3 O 6.77 as a copper-deficient non-stoichiometric compound.