| Numéro |
J. Phys. IV France
Volume 07, Numéro C1, Mars 1997
7th INTERNATIONAL CONFERENCE ON FERRITES
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|---|---|---|
| Page(s) | C1-509 - C1-512 | |
| DOI | https://doi.org/10.1051/jp4:19971208 | |
J. Phys. IV France 07 (1997) C1-509-C1-512
DOI: 10.1051/jp4:19971208
Static and Dynamical Properties of γ-Fe2O3 Nanoparticles
J.L. Dormann1, A. Ezzir1, R. Cherkaoui1, M. Nogues1, F. Lucari2, F. d'Orazio2, M. Godinho3, E. Tronc4, J.P. Jolivet4 and D. Fiorani51 LMOV, CCNR-Université de Versailles, 78035 Versailles cedex, France
2 Universita, 67010 L'Aquila, Italia
3 Dep. de Fisica, Univ. de Lisboa, 1700 Lisboa, Portugal
4 Université P. et M Curie, 75250 Paris cedex 05, France
5 IC-MAT, CNRS, 00016 Monterotondo Stazione, Italia
Abstract
Several series of γ-Fe2O3 nanoparticles dispersed in a polymer have been studied by means of various techniques. The variation of the relaxation time of the magnetic moment of the particle is in very good agreement with the Néel-Brown and our interparticle interaction models which lead to a reduced damping constant varying between 0.08 and 1. For non interacting particles, the main component of the anisotropy comes from the surface. For interacting particles, the interaction energy includes dipolar and surface induced contributions. The susceptibility in the superparamagnetic state shows a strong dependence of the results on the external shape of the sample and the direction of applied field, very well checked experimentally, which is well interpreted with the Onsager model.
© EDP Sciences 1997