Influence of Electric and Magnetic Fields on Dielectric Response of Oil-Based Ferrofluid

Š. Hardoňa, J. Kúdelčíka, P. Burya, M. Guttenb aDepartment of Physics, University of Žilina, Univerzitná 1, 010 26 Žilina, Slovakia bDepartment of Measurement and Applied Electrical Engineering, University of Žilina, Univerzitná 1, 010 26 Žilina, Slovakia

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The changes in dielectric parameters and structural arrangement of transformer oil based ferrofluid with magnetic nanoparticles upon the effect of an external magnetic field and an electric field were studied by dielectric spectroscopy. The frequency dependence of dissipation factor was measured within the frequency range from 1 mHz to 10 kHz by a capacitance method. In the presence of the magnetic field the interaction between the magnetic field and magnetic moments of nanoparticles led to the aggregation of nanoparticles. The electric field had also effects on the change in the electric dipole moment of particles by transfer of counterions. The observed low frequency relaxation maximum of dissipation factor was explained by Schwarz theory of electric double layer polarization. The shift of this maximum with the intensity of electric was caused by change of relaxation time of the nanoparticles-counterions systems.

DOI: 10.12693/APhysPolA.133.477 PACS numbers: 47.65.Cb, 77.22.Gm, 77.22.Ch, 75.50.Mm, 75.75.Jn