Surface and bulk characteristics of the single phase high Tc superconductor YBaCuO3−n

Determination of oxygen content and metal valences in oxide superconductors by chemical methods

“…From the two thermogravimetric approaches, the reduction method has to be preferred as the measurement connected to the synthesis of the material cannot be repeated for already existing samples [33]. Besides the indirect chemical methods mentioned above, various direct measurements of the evolved oxygen gas produced either upon (i) acidic dissolution [34][35][36][37][38] or (ii) heating up [39] the sample have also been proposed. These kinds of volumetric methods have typically been used for the characterization of non-stoichiometric metal nitrides and hydrides [40].…”

Materials and Models: Faces of Intercalation Chemistry

“…As discussed already above, rare earth oxocuprates (RE) Ba2Cu307 have been found to be able to intercalate and deintercalate oxygen in a topotactic process at rather low temperatures of circa 400°C (Equation 18). It has been suggested early after the discovery of superconductivity in these phases which formally contain Cu3+ in a local model (e.g., y3+(Ba2+h(Cu 2 +)z(Cu3+)(02-h) that peroxide or peroxide like oxygen anion states are present in the lattice [347,348]. One of the aspects related to this phenomenon is the question why oxygen should be easily mobile in ceramic oxides with high lattice energy at unusually low temperatures.…”