Charge transfer in spinel Co3O4 at high pressures
Ligang Bai1, Michael Pravica, Yusheng Zhao
1Department of Physics and Astronomy, University of Nevada Las Vegas and High Pressure Science and Engineering Center (HiPSEC), Las Vegas, NV 89154-4002, USA. BaiLg@hpcat.aps.anl.gov
Summary
High pressure studies reveal charge transfer in cobalt oxide (Co(3)O(4)) at 17.7 GPa, causing a structural transition from normal to partially inverse spinel. This highlights pressure-induced electronic changes in materials.
Area of Science:
- Materials Science
- Solid-State Physics
- Inorganic Chemistry
Background:
- Cobalt oxide (Co(3)O(4)) exhibits a spinel structure with potential for pressure-induced electronic and structural modifications.
- Understanding these changes is crucial for applications involving materials under extreme conditions.
Purpose of the Study:
- To investigate charge transfer and structural transitions in Co(3)O(4) under high pressure.
- To elucidate the relationship between pressure, structure, and electronic properties.
Main Methods:
- High-pressure experiments utilizing X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) spectroscopy, and Raman scattering.
- Structural data refinement and calculation of the mode Grüneisen parameter.
Main Results:
- The cubic spinel structure of Co(3)O(4) was maintained up to 42.1 GPa.
- A structural transition from normal to partially inverse spinel was observed above 17.7 GPa.
- Changes in XANES pre-edge features provided evidence for charge transfer between tetrahedral and octahedral sites.
Conclusions:
- High pressure induces a charge transfer process in Co(3)O(4), leading to a partial inverse spinel structure.
- The observed transition is attributed to charge interactions between different crystallographic sites.
- Experimental techniques like XRD, XANES, and Raman scattering are effective in probing pressure-induced phenomena in oxides.
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