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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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Frandsen, Cathrine
Technical University of Denmark
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (19/19 displayed)
- 2022Order and Disorder in Layered Double Hydroxides: Lessons Learned from the Green Rust Sulfate-Nikischerite Seriescitations
- 2018Dipolar-coupled moment correlations in clusters of magnetic nanoparticlescitations
- 2017Induced Mesocrystal-Formation, Hydrothermal Growth and Magnetic Properties of α-Fe2O3 Nanoparticles in Salt-Rich Aqueous Solutionscitations
- 2017Off-axis spin orientation in goethite nanoparticlescitations
- 2017Effect of carbon on interstitial ordering and magnetic properties of ε-Fe2(N,C)1-zcitations
- 2017Spin orientation in solid solution hematite-ilmenitecitations
- 2017Effect of carbon on interstitial ordering and magnetic properties of ε-Fe2(N,C) 1-zcitations
- 2016Composition-dependent variation of magnetic properties and interstitial ordering in homogeneous expanded austenitecitations
- 2016Composition-dependent variation of magnetic properties and interstitial ordering in homogeneous expanded austenitecitations
- 2015In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteriescitations
- 2015Reversible guest binding in a non-porous FeII coordination polymer host toggles spin crossovercitations
- 2015Polarized neutron powder diffraction studies of antiferromagnetic order in bulk and nanoparticle NiOcitations
- 2015Reversible guest binding in a non-porous Fe II coordination polymer host toggles spin crossovercitations
- 2012Direction-specific interactions control crystal growth by oriented attachment.citations
- 2012Electron small polarons and their mobility in iron (oxyhydr)oxide nanoparticles.citations
- 2011Spin reorientation in α-Fe2O3 nanoparticles induced by interparticle exchange interactions in alpha-Fe2O3/NiO nanocompositescitations
- 2009Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopycitations
- 2004Interparticle interactions in composites of nanoparticles of ferrimagnetic (gamma-Fe2O3) and antiferromagnetic (CoO,NiO) materialscitations
- 2003Inter-particle Interactions in Composites of Antiferromagnetic Nanoparticles
Places of action
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article
Induced Mesocrystal-Formation, Hydrothermal Growth and Magnetic Properties of α-Fe2O3 Nanoparticles in Salt-Rich Aqueous Solutions
Abstract
Iron oxide nanoparticles are widely prevalent in our aqueous environment (e. g., streams, seawater, hydrothermal vents). Their aggregation and crystal growth depend on their chemical surroundings, for instance just a change in pH or salt concentration can greatly affect this. In turn this influences their properties, mobility, fate, and environmental impact. We studied the growth of α-Fe<sub>2</sub>O<sub>3</sub> (hematite), starting from 8 nm hematite particles in weakly acidic (HNO3) aqueous suspension with different states of particle aggregation, using salt (NaCl and NaH2PO4) to control their initial aggregation state. The samples were then subject to hydrothermal treatment at 100-140 degrees C. We followed the development in aggregation state and particle size by dynamic light scattering, X-ray diffraction, small angle neutron scattering and transmission electron microscopy, and the magnetic properties by Mossbauer spectroscopy. The addition of NaCl and NaH2PO4 both led to aggregation, but NaCl led to linear chains of hematite nanoparticles (oriented parallel to their hexagonal c-axis), such that the crystalline lattice planes of neighboring hematite particles were aligned. However, despite this oriented alignment, the particles did not merge and coalesce. Rather they remained stable as mesocrystals until heat-treated. In turn, the addition of NaCl significantly increases the rate of growth during hydrothermal treatment, probably because the nanoparticles, due to the chain formation, are already aligned and in close proximity. With hydrothermal treatment, the magnetic properties of the particles transform from those characteristic of small (aggregated) hematite nanoparticles to those of particles with more bulk-like properties such as Morin transition and suppression of superparamagnetic relaxation, in correspondence with the growth of particle size.