The Response of a Magnetic Fluid to Radio Frequency Electromagnetic Field
B. Dolníka, M. Rajňáka,b, R. Cimbala a, I. Kolcunová a, J. Kurimský a, J. Balogh a, J. Džmura a, J. Petráš a, P. Kopčanský b, M. Timko b, J. Briančin c and M. Fabián c
aDepartment of Electrical Power Engineering, TU of Košice, Mäsiarska 74, 041 20 Košice, Slovakia
bInstitute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice, Slovakia
cInstitute of Geotechnic, SAS, Watsonova 45, 043 53 Košice, Slovakia
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Electromagnetic pollution generated by the electrical devices has been regarded as a new form: of pollution, harmful to the society as air and water pollution. The operation of electronic devices in a polluted electromagnetic environment has caused electromagnetic interference to become important concerns. Devices that are vulnerable to interference must often be shielded to protect them from the effects of electromagnetic interference. In this work we describe an interaction of a magnetic fluid based on transformer oil with alternating magnetic field. The magnetic fluid was composed of a transformer oil and dispersed magnetite nanoparticles coated with oleic acid. Among the wide range of topics covered, we pay attention to an important field related to the absorption of electromagnetic field by magnetic fluid as a suitable candidate for applications where it is necessary to electrically isolate, remove excess of heat, and to shield electromagnetic fields. We present a method for the determination of shielding effectiveness of the magnetic fluid under high-frequency excitation conditions from 750 MHz to 3 GHz by means of magnetic near field measurements and analysis. Herein, we report the effect of magnetic volume fraction in the magnetic fluid and the effect of the sample thickness on the shielding effectiveness. We have found that the magnetic fluid has a frequency dependent "windows", characterized that either absorb the magnetic field, or facilitate penetration of the magnetic field through the barrier.

DOI: 10.12693/APhysPolA.131.946
PACS numbers: 41.20.Jb, 41.20.Gz, 75.50.Mm, 81.70.Ex, 07.50.Hp