Dielectric anisotropy of the magnetic fluid cobalt ferrite in dibutylphthalate

This paper presents an experimental dielectric study of a ferrofluid, magnetic particles of CoFe₂O₄ dispersed in dibutylphthalate at different volume concentrations over a large temperature range (40 to -100°C), between 1 mHz and 10 MHz, with and without a continuous axial or radial magnetic field. The analysis of static permittivity indicates that the magnetodielectric anisotropy which exists at room temperature, persists at lower temperature, near the glass transition temperature of the carrier liquid. Moreover these results show a possible existence and growth of aggregates at the upper concentrations of ferrites. The position of the relaxation peaks of different solutions is modified by the presence of an axial continuous magnetic field