Electronic edition ISSN 1574-0579

Dielectric properties of magnetic fluids based on transformer oil ITO 100 in a high frequency electric field

M. Rajnak¹ - M. Timko¹ - L. Tomco² - K. Marton³ - J. Kurimsky³ - B. Dolnik³ - R. Cimbala³ - M. Molcan¹ - P. Kopċanský¹

¹ Institute of Experimental Physics SAS, Watsonova 47, 040 01Košice, Slovakia
² Faculty of Aeronautic, Technical University, Rampova 7, 041 21 Košice, Slovakia
³ Faculty of Electrical Engineering and Informatics Technical University, Letna 9, 042 00 Košice, Slovakia

Abstract
We have studied dielectric properties (complex permittivity and dielectric loss factor) of a transformer oil ITO 100 based magnetic fluid with various concentrations of magnetic Fe₃O₄ nanoparticles covered with oleic acid as a surfactant. The experiments were carried out at different volume concentrations of magnetite nanoparticles up to 4 0x0p+0t room temperature and in a frequency range from 100 Hz up to 2 MHz, with and without external magnetic field up to 30 mT. The linear increase of the dielectric constant with volume concentration has been confirmed. The presence of magnetic field causes the increase of the real part of complex permittivity and the decrease of both the imaginary part of complex permittivity and the dielectric loss factor. Figs 3, Refs 5.