Oxidation state of a buried interface: Near-edge x-ray fine structure of a crystal truncation rod
- Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6118 (United States)
We observe that the crystal-truncation-rod (CTR) diffraction from the Al[sub 2]O[sub 3] substrate of an Al[sub 2]O[sub 3]/Cr[sub 2]O[sub 3](001) interface has fine structure when the x-ray energy is tuned through the Cr [ital K] absorption edge. This fine structure is attributed to interference between scattering from the substrate and Cr atoms at the interface, which are coherent with the substrate. Comparisons with x-ray-absorption spectra of standard samples demonstrate that the Cr at the interface is predominantly in the Cr[sup 3+] oxidation state. We demonstrate how the near-edge energy dependence of the CTR diffracted intensity may be used to deduce the amplitude [ital and] [ital phase] of the interface scattering. This phase information is used in conjunction with reciprocal-lattice-vector-dependent measurements of diffracted power due to CTR's to deduce the structure of the Cr[sub 2]O[sub 3]/Al[sub 2]O[sub 3] interface. While the local atomic coordination at the interface is the same as that of Al[sub 2]O[sub 3] and Cr[sub 2]O[sub 3], there is a stacking fault at the interface covering half of the interface area.
- DOE Contract Number:
- AC05-84OR21400; AC02-76CH00016
- OSTI ID:
- 6542390
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 47:20; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM OXIDES
FINE STRUCTURE
CHROMIUM OXIDES
OXIDATION
CHEMISORPTION
CRYSTAL STRUCTURE
INTERFACES
SORPTIVE PROPERTIES
X-RAY DIFFRACTION
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties