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Journal of Nanomaterials
Volume 2007 (2007), Article ID 34527, 11 pages
http://dx.doi.org/10.1155/2007/34527
Research Article

On the Dielectric and Magnetic Properties of Nanocomposites

1Fachrichtung 7.2, Experimentalphysik, Universität des Saarlandes, Postfach 151150, Saarbrücken 66041, Germany
2Institut für Verbundwerkstoffe GmbH (IVW), Erwin-Schrödinger-Straße, Gebäude 58, Kaiserslautern 67663, Germany

Received 15 February 2007; Revised 29 June 2007; Accepted 17 October 2007

Academic Editor: C. Brosseau

Copyright © 2007 B. Hallouet et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigate nanocomposites, that is, dispersions of magnetite nanoparticles in an epoxy resin, by means of broadband dielectric and magnetic spectroscopy. The molecular dynamics of the polymer matrix is altered by the nanoparticles. Due to the formation of agglomerates neither permittivity nor permeability can be described with known effective medium models. We use the spectral representation (Bergman theorem) to show that a model-free evaluation of the low-frequency permeability of the nanoparticles can be achieved by combining dielectric and magnetic data. In addition, the ferromagnetic resonance is studied experimentally. It occurs near 3 GHz and is independent of the particle concentration.