L. Jorat et al., DIELECTRIC ANISOTROPY OF THE MAGNETIC FLUID COBALT FERRITE IN DIBUTYLPHTHALATE, IEEE transactions on dielectrics and electrical insulation, 1(3), 1994, pp. 365-370
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.