Moore, Elaine; Bohorquez, A.; Berry, Frank; Helgason, O. and Marco, J.F.
This is the latest version of this eprint.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1016/S0022-3697(01)00021-X|
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Results from atomistic simulation calculations and X-ray photoelectron spectroscopy are used to define the proposed defect structures of gamma-Fe2O3 and Fe3O4 doped with tetravalent ions. These structures are of interest because of the effect of doping on the properties of the oxides. Calculations confirm that occupation by Sn4+ and Ti4+ of octahedral sites in Fe3O4 and gamma-Fe2O3 is more favourable than occupation of tetrahedral asites and indicate that the M4+ ions substitute on iron sites rather than occupy interstitial sites. For gamma-Fe2O3, XPS shows no reduction of Fe3+ occurs. Of the possible remaining balancing defects, calculations indicate that vacancies on the iron sites with six nearest-neighbour iron atoms are favoured. In the case of Fe3O4 results suggest that reduction of Fe3+ to Fe2+ is preferred and that reduction occurs on a site adjacent to M4+. This small cluster localises the disruption to the crystal structure. These results suggest that the pattern of doping by tetravalent ions in spinel-related iron oxides differs from that in the corundum-related alpha-Fe2O3.
|Item Type:||Journal Article|
|Keywords:||oxides; ceramics; defects|
|Academic Unit/Department:||Science > Life, Health and Chemical Sciences|
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Biomedical Research Network (BRN)
|Depositing User:||Users 1688 not found.|
|Date Deposited:||19 Oct 2006|
|Last Modified:||07 Mar 2014 13:41|
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Investigation of defect structures formed by doping tetravalent ions into spinel-related iron oxides using atomistic simulation calculations. (deposited 14 Nov 2006)
- Investigation of defect structures formed by doping tetravalent ions into spinel-related iron oxides using atomistic simulation calculations. (deposited 19 Oct 2006) [Currently Displayed]