Dielectric and magnetic response of Fe3O4/epoxy composites

RAMAJO, L.A.; CRISTÓBAL, A.A.; BOTTA, P.M.; PORTO LÓPEZ, J.M.; REBOREDO, M.M.; CASTRO, M.S.

COMPOSITES. PART A, APPLIED SCIENCE AND MANUFACTURING

Elsevier

Lugar: Amsterdam; Año: 2008 vol. 40 p. 388 - 393

1359-835X

Magnetic and dielectric properties of Fe3O4/epoxy resin composites were studied as a function of Fe3O4concentration. The Fe3O4 powder was milled using a planetary ball-mill in order to reduce the particlesize. B.E.T. area of these particles was determined, and a structural characterization was performed byX-ray diffraction (XRD). Fe3O4/epoxy composites were prepared mixing the raw materials and pouringthem into suitable moulds. Dielectric measurements were performed at different frequencies and temperatures,while magnetic properties were assessed at different temperatures. It was found that permittivitywas strongly dependent on the filler concentration and frequency. Maxwell–Wagner–Sillarsinterfacial polarization, Intermediate Dipolar Polarization (IDE), and a relaxation process were responsiblefor the observed behavior. Magnetic measurements revealed the presence of magnetite nanoparticlesin the composites, with a blocking temperature close to 170 K.