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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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Johannessen, B.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (12/12 displayed)
- 2011Extended x-ray absorption fine structure study of porous GaSb formed by ion implantationcitations
- 2010Ion-irradiation-induced amorphization of cobalt nanoparticlescitations
- 2007Modification of embedded Cu nanoparticlescitations
- 2007Synthesis and characterization of ion-implanted Pt nanocrystals in SiO2citations
- 2007Formation and characterization of nanoparticles formed by sequential ion implantation of Au and Co into SiO2citations
- 2007Ion-irradiation-induced amorphization of Cu nanoparticles embedded in SiO2citations
- 2007Amorphization of embedded Cu nanocrystals by ion irradiationcitations
- 2006Structural stability of Cu nanocrystals in SiO2 exposed to high-energy ion irradiationcitations
- 2006Size-dependent structural disorder in nanocrystalline Cu probed by synchrotron-based X-ray techniquescitations
- 2005EXAFS comparison of crystalline/continuous and amorphous/porous GaSbcitations
- 2005Irradiation induced defects in nanocrystalline Cucitations
- 2005Disorder in Au and Cu nanocrystals formed by ion implantation into thin SiO2citations
Places of action
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article
Ion-irradiation-induced amorphization of cobalt nanoparticles
Abstract
<p>The amorphization of Co nanoparticles embedded in SiO2 has been investigated by measuring their structure and size, before and after ion irradiation, by x-ray absorption spectroscopy and small-angle x-ray scattering, respectively. Compared to bulk material, unirradiated crystalline nanoparticles exhibited increased structural disorder and a decreased average coordination number as a result of finite-size effects. Upon irradiation, there was no variation in nanoparticle size yet significant structural change. The coordination number decreased further while the mean value (bondlength), variance (Debye-Waller factor), and asymmetry (third cumulant) of the interatomic distance distribution all increased, as consistent with theoretical predictions for an amorphous elemental metal. Furthermore, the interatomic distance distribution for irradiated Co nanoparticles was in excellent agreement with our molecular dynamics simulations for bulk amorphous Co, and we have thus attributed the observed structural changes to the formation of an amorphous phase. Though such a crystalline-to-amorphous phase transformation is not readily achievable in bulk material by ion irradiation, we suggest that the perturbed structural state prior to irradiation and the amorphous surrounding matrix both contribute to nucleating and stabilizing the amorphous phase in irradiated Co nanoparticles. In addition to the structural properties, the vibrational properties of the amorphous phase were also probed, using temperature-dependent x-ray absorption spectroscopy measurements. The Einstein temperature of the unirradiated crystalline nanoparticles was lower than that of bulk material due to loosely bonded surface/interfacial atoms. In contrast, that of the irradiated amorphous nanoparticles was substantially higher than the bulk value. We attribute this apparent bond stiffening to the influence of the rigid surrounding matrix.</p>