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| HAL: hal-00171689, version 1 |
| DOI: 10.1088/0957-4484/18/28/285606 |
| Detailed view |  Export this paper |
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| Nanotechnology 18, 28 (2007) 285606 |
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| Synthesis and characterization of core-shell structure silica-coated Fe29.5Ni70.5 nanoparticles |
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| Mehdi Ammar 1, 2Frédéric Mazaleyrat 1, 2 |
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| (2007) |
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| In view of potential applications of magnetic particles in biomedicine and electromagnetic devices, we made use of the classical Stober method-base-catalyzed hydrolysis and condensation of tetraethoxysilane (TEOS)-to encapsulate FeNi nanoparticles within a silica shell. An original stirring system under high power ultrasound made it possible to disperse the otherwise agglomerated particles. Sonication guaranteed particles remained dispersed during the Stober synthesis and also improved the efficiency of the method. The coated particles are characterized by electron microscopy (TEM) and spectroscopy (EDX) showing a core-shell structure with a uniform layer of silica. Silica coating does not affect the core magnetic properties. Indeed, all samples are ferromagnetic at 77 K and room temperature and the Curie point remains unchanged. Only the coercive force shows an unexpected non-monotonic dependence on silica layer thickness. |
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| 1: | Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE) |
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CNRS : UMR8029 – École normale supérieure de Cachan - ENS Cachan |
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| 2: | Institut d'Alembert (IA) |
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École normale supérieure de Cachan - ENS Cachan – CNRS : IFR121 |
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| 3: | Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM) |
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CNRS : UMR8531 – École normale supérieure de Cachan - ENS Cachan |
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| 4: | Institut de Chimie et des Matériaux Paris-Est (ICMPE) |
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CNRS : UMR7182 – Université Paris-Est Créteil Val-de-Marne (UPEC) |
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| Subject | : | Chemical Sciences/Theoretical and/or physical chemistry Chemical Sciences/Material chemistry |
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| MAGNETIC-PROPERTIES – PARTICLES – NANOCOMPOSITES – FE – ALLOYS – FILMS – SIZE |
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| hal-00171689, version 1 | |
| http://hal.archives-ouvertes.fr/hal-00171689 | |
| oai:hal.archives-ouvertes.fr:hal-00171689 | |
| From: Rémi Métivier | |
| Submitted on: Wednesday, 12 September 2007 17:51:45 | |
| Updated on: Wednesday, 19 March 2008 17:31:42 | |
