Formation of {gamma}-Fe{sub 2}O{sub 3} nanoparticles and vacancy ordering: An in situ X-ray powder diffraction study
- Chemistry Department, University of Aarhus, DK-8000 Arhus C (Denmark)
- Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)
The formation of maghemite, {gamma}-Fe{sub 2}O{sub 3} nanoparticles has been studied by in situ X-ray powder diffraction. The maghemite was formed by thermal decomposition of an amorphous precursor compound made by reacting lauric acid, CH{sub 3}(CH{sub 2}){sub 10}COOH with Fe(NO{sub 3}){sub 3}.9H{sub 2}O. It has been shown that cubic {gamma}-Fe{sub 2}O{sub 3} was formed directly from the amorphous precursor and that vacancy ordering starts about 45 min later at 305 deg. C resulting in a tripled unit cell along the c-axis. The kinetics of grain growth was found to obey a power law with growth exponents n equal to 0.136(6) and 0.103(5) at 305 and 340 deg. C, respectively. Particles with average sizes of 12 and 13 nm were obtained in 86 and 76 min at 305 and 340 deg. C, respectively. The structure of cubic and vacancy ordered phases of {gamma}-Fe{sub 2}O{sub 3} was studied at 305 deg. C by Rietveld refinements. - Graphical abstract: Stack of powder diagrams showing the formation of {gamma}-Fe{sub 2}O{sub 3} nanoparticles and subsequent vacancy ordering at 305 deg. C.
- OSTI ID:
- 21015635
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 1; Other Information: DOI: 10.1016/j.jssc.2006.09.033; PII: S0022-4596(06)00534-2; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nanoneedles of maghemite iron oxide prepared from a wet chemical route
Synthesis of Fe/SiO{sub 2} and iron oxides/SiO{sub 2} nanocomposites by long-term ball milling