Surface structure of magnetite (111) under hydrated conditions by crystal truncation rod diffraction

X-ray crystal truncation rod (CTR) diffraction under hydrated conditions at circum-neutral pH was used to determine the surface structure of Fe 3O 4(111) following a wet chemical mechanical polishing (CMP) preparation method. The best-fit model to the CTR data shows the presence of two oxygen termin...

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Bibliographic Details
Published in:Surface science 2010-07, Vol.604 (13), p.1082-1093
Main Authors: Petitto, Sarah C., Tanwar, Kunaljeet S., Ghose, Sanjit K., Eng, Peter J., Trainor, Thomas P.
Format: Article
Language:English
Subjects:
Bonding
Chemical mechanical polished (CMP)
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Crystal structure
Crystal Truncation Rod (CTR) Diffraction
Diffraction
Exact sciences and technology
Iron
Magnetite
Magnetite (Fe 3O4)
Mechanical polishing
Physics
Surface chemistry
Surface structure
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Summary:X-ray crystal truncation rod (CTR) diffraction under hydrated conditions at circum-neutral pH was used to determine the surface structure of Fe 3O 4(111) following a wet chemical mechanical polishing (CMP) preparation method. The best-fit model to the CTR data shows the presence of two oxygen terminated domains that are chemically inequivalent and symmetrically distinct in the surface contribution ratio of 75% oxygen octahedral-iron (OOI) termination ( aO 2.61– aO 1.00– oh1Fe 2.55– bO 1.00– bO 3.00– td1Fe 1.00– oh2Fe 1.00– td2Fe 1.00–R) to 25% oxygen mixed-iron (OMI) termination ( bO 1.00– bO 3.00– td1Fe 0– oh2Fe 1.00– td2Fe 1.00– aO 3.00– aO 1.00– oh1Fe 3.00–R). An adsorbed water layer could not be constrained in the best-fit model. However, bond-valence analyses suggest that both of the surfaces are hydro-oxo terminated. Furthermore, the topmost iron layers of both domains are inferred to be occupied with the redox active Fe 2+ and Fe 3+ cations indicating that these irons are the principle irons involved in controlling the surface reactivity of magnetite in industrial and environmentally relevant conditions.
ISSN:0039-6028
1879-2758
DOI:10.1016/j.susc.2010.03.014