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Oxygen ordering and mobility in YBaCo(4)O(7+delta)
Yan Jia1, Hua Jiang, Markus Valkeapää
1NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, P.O. Box 5100, FI-02015 TKK, Finland.
Journal of the American Chemical Society
|March 14, 2009
Summary
Researchers discovered remarkable oxygen ordering and mobility in YBaCo(4)O(8.5), a mixed-valence cobalt oxide. Electron-beam irradiation revealed reversible oxygen migration, advancing understanding of diffusion in transition-metal oxides.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Oxide Materials
Background:
- Mixed-valence cobalt oxides exhibit complex structural and electronic properties.
- Understanding oxygen stoichiometry and diffusion is crucial for applications like catalysis and energy storage.
Purpose of the Study:
- To investigate the ordering and mobility of excess oxygen in YBaCo(4)O(8.5).
- To explore the impact of electron-beam irradiation on oxygen migration and structural stability.
Main Methods:
- Synthesis of oxygen-nonstoichiometric YBaCo(4)O(8.5).
- In-situ observation of oxygen migration using intense electron-beam irradiation.
- Analysis of reversible structural modulation transitions.
Main Results:
- Extraordinary oxygen ordering and high mobility were observed in YBaCo(4)O(8.5).
- Excess oxygen atoms incorporate into the YBaCo(4)O(7) lattice in various configurations.
- Electron-beam heating induced reversible oxygen migration and structural modulations.
Conclusions:
- The YBaCo(4)O(8.5) structure exhibits a high degree of freedom for surplus oxygen.
- This study provides insights into oxygen diffusion mechanisms in transition-metal oxides.
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