Dielectric Spectroscopy of Two Concentrations of Magnetic Nanoparticles in Oil-Based Ferrofluid

Š. Hardoňa, J. Kúdelčíka, M. Guttenb aDepartment of Physics, Faculty of Electrical Engineering and Information Technology, University of Žilina, 010 26, Slovakia bDepartment of Measurement and Applied Electrical Engineering, Faculty of Electrical Engineering and Information Technology, University of Žilina, 010 26, Slovakia

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The study of the changes of dielectric parameters leads to a better understanding of polarization and relaxation phenomena in ferrofluids. The impacts of the electric field and magnetic flux density cause the changes in dielectric parameters and structural arrangement of magnetic nanoparticles in ferrofluid and this effect has been studied by using dielectric spectroscopy. The frequency dependence of tan(δ) was measured within the frequency range from 1 mHz to 10 kHz and in a wide range of temperatures from -25° to 25°. Magnetic flux density and electric field were applied by a capacitance method. The object of our study was the ferrofluid with two different concentrations of magnetic nanoparticles in transformer oil MOL. The dielectric parameters were measured at parallel and perpendicular orientations of the magnetic flux density with value of 200 mT to the electric field as a function of temperature. The Cole-Cole relaxation model was used for analysing measured data. From this model, basic dielectric parameters as a function of temperature were determined for different fields.

DOI:10.12693/APhysPolA.137.961 topics: dielectric spectroscopy, ferrofluid, nanoparticles