Distribution of Oxygen Atoms in a YBa2Cu3O6.4 Superconductor Visualized by Ultra-High-Resolution Electron Microscopy
- 1 September 1992
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 31 (9B) , L1335-1338
- https://doi.org/10.1143/jjap.31.l1335
Abstract
Arrangements of oxygen atoms in a superconducting YBa2Cu3O6.4 crystal (T c=27 K) have been visualized by ultra-high-resolution high-voltage electron microscopy. The crystal consists of major orthorhombic and minor pseudotetragonal regions. Oxygens in CuO y planes do not distribute homogeneously but are mostly concentrated in areas smaller than 100 Å in diameter, in which clusters of 8 to 30 Å are closely packed with an oxygen arrangement similar to that in YBa2Cu3O6.9 or YBa2Cu3O7.7 respectively. The volume ratio of these two types of clusters varies in each area, resulting in the local change of the crystal symmetry. The formation of these oxygen-rich areas as well as clusters must strongly affect the mechanism and properties of superconductivity.Keywords
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