DIELECTRIC ANISOTROPY OF THE MAGNETIC FLUID COBALT FERRITE IN DIBUTYLPHTHALATE

This paper presents an experimental dielectric study of a ferrofluid, magnetic particles of Fe2CoO4 dispersed in dibutyl phthalate at differ ent volume concentrations over a large temperature range (40 to -100-d egrees-C), between 1 mHz and 10 MHz, with and without a continuous axi al or radial magnetic field. The analysis of static permittivity indic ates that the magneto-dielectric anisotropy which exists at room tempe rature, persists at lower temperature, near the glass transition tempe rature of the carrier liquid. Moreover these results show a possible e xistence and growth of aggregates at the upper concentrations of ferri tes. The position of the relaxation peaks of different solutions is mo dified by the presence of an axial continuous magnetic field.