The crystal structure of a cuprate containing CO3 groups, (C0.58Cu0.42)(Sr0.88Ca0.12)2(Y0.50Ca0.26Sr0.24)Cu2O7, and its high-pressure oxygen-annealed samples were refined by means of the Rietveld method for neutron-powder-diffraction data. The as-prepared sample (non-superconducting) has neither oxygen defect nor carbonate defect in the structure. Noticeable absence of oxygen atoms and carbonate groups are detected for the annealed (superconducting) sample. It is suggested that hole doping is achieved during high-pressure oxygen annealing by the release of some CO3 groups and by the introduction of oxygen atoms into the vacant 'apical' oxygen site, when the CO3 group is not present.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering