Oxygen ordering, phase separation and the 60-K and 90-K plateaus in YBa2Cu3O(x)
Abstract
Ordered oxygen structures and superconducting properties of YBa2Cu3O(x) samples prepared in precisely controlled oxygen environments using a solid-state ionic technique are reported. No evidence is found for phase separation between structures that have widely different oxygen content, but electron diffraction evidence is seen for phase separation between distinct phases that differ only slightly in oxygen content. These regions of phase separation coincide with the superconducting transition temperature plateaus of YBa2Cu3O(x) at about 60 K and about 90 K. These results show that the commonly held view that the two plateaus correspond to single-phase regions of respective 60-K and 90-K phases is incorrect: the changes in superconducting properties with oxygen content in YBa2Cu3O(x) cannot be explained on this basis.
- Publication:
-
Nature
- Pub Date:
- August 1989
- DOI:
- 10.1038/340619a0
- Bibcode:
- 1989Natur.340..619B
- Keywords:
-
- Copper Oxides;
- High Temperature Superconductors;
- Mixed Oxides;
- Phase Separation (Materials);
- Transition Temperature;
- Barium Oxides;
- Electron Diffraction;
- Oxygen;
- Yttrium Oxides;
- Solid-State Physics