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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Moore, Elaine
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (8/8 displayed)
- 2011Formation, cationic site exchange and surface structure of mechanosynthesized EuCrO<sub>3</sub> nanocrystalline particlescitations
- 2009The Formation of Nanocrystalline SrFeO3−δ Using Mechano-Synthesis and Subsequent Sintering: Structural and Mössbauer Studiescitations
- 2008Synthesis and structural investigation of a new oxide fluoride of composition Ba2SnO2.5F3·xH2O (x≈0.5)citations
- 2008Magnetic order in perovskite-related SrFeO<sub>2</sub>F
- 2007Iron(III) as a defect in diantimony tetroxidecitations
- 2002Tin-, titanium-, and magnesium-doped alpha-Cr2O3: characterisation and rationalisation of the structurescitations
- 2002Prediction of defect structure in lithiated tin- and titanium-doped alpha-Fe2O3 using atomistic simulationcitations
- 2001Investigation of defect structures formed by doping tetravalent ions into spinel-related iron oxides using atomistic simulation calculationscitations
Places of action
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article
The Formation of Nanocrystalline SrFeO3−δ Using Mechano-Synthesis and Subsequent Sintering: Structural and Mössbauer Studies
Abstract
The influence of mechanical milling and subsequent sintering of a 2:1 molar mixture of SrCO3 and α-Fe2O3 on the formation of SrFeO3−δ pervoskite-related nanocrystalline particles is investigated. The structural evolution during the formation process is systematically investigated using X-ray diffraction, thermal analysis, X-ray photoelectron spectroscopy and Mössbauer spectroscopy. Premilling the mixture in air for 120 h leads to the incorporation of Sr2+ in the α-Fe2O3 crystal structure thus facilitating the formation of a 2:1 nanocrystalline mixture of SrFeO3 and SrFeO2.875 by sintering the pre-milled mixture in air at 800 °C (12 h). This temperature is ∼300 °C lower than those at which SrFeO3−δ phases are synthesized by the conventional ceramic techniques. Pre-milling the precursors was found to result in a smaller oxygen deficiency (δ) relative to conventional ceramic synthesis of SrFeO3−δ. Rietveld refinement of the X-ray diffraction shows the interatomic distances in the resulting SrFeO2.875 nanocrystalline phase to be slightly different from those of the conventionally prepared bulk leading, in turn, to a crystal structure with tilted polyhedral cationic sites. This structural distortion is related to both small-size and surface effects in the nanoparticles that have no counterparts in the corresponding bulk material. The surface structure of the attained SrFeO3−δ nanocrystalline particles shows a significant partial reduction of Fe4+ to Fe3+ due to ambient conditions and the presence of an appreciable amount of SrCO3 as well.