| || Nickel-substituted Lithium-Zinc-Manganese Ferrite for the Suppression of Radiated Emission Noise
Author : Joshi, N. C.;Verma, Anjali;Kumar, Nitendar;Islam, S. S.;Kumar, O. B. Satheesh
Source : Defence Science Journal ; Vol:57(4) ; 2007 ; pp 471-480
Subject : 620.1 Material Science and Technology
Keywords : Electromagnetic interference suppression;EMI suppression;Ceramic ferromagnetic materials;Nickel-substituted fererites;EMI control;Noise–suppression;Eletromagnetic compatibility;Lithium ferrites
Abstract : Nickel-substituted lithium-zinc-manganese ferrite of the composition, Li0.25-x/4 Zn0.5-x/2NixMn 0.1 Fe2.15-x/4O4 where x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 have been investigated for electromagnetic interference (EMI) suppression to meet the EMI standards. Various compositions were prepared by the conventional ceramic technique using mixed oxides. The ferrites were characterised for their structural, electrical, and magnetic, properties. The ferrites were found to posses high saturation magnetisation, permeability, Curie temperature and resistivity, which are the desirable characteristics for noise-suppression application. The operating frequency of the ferrite ranged from 1 MHz–700 MHz, which is high enough for absorbing the electrical fast transients and radiated emission noise suppression as shown for three devices–currency counting machine, energy meter and dc-dc converter where the radiated emission noise is suppressed from 10 dB to 20 dB. In energy meter where the electrical fast transients (EFTs) are suppressed up to 5.5 kV, 4.5 kV, 3.5 kV, 2.8 kV, 1.6 kV, and 1.2 kV with composition x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, respectively. This material has tremendous scope of application in military equipment to comply the EMI requirements of the military standards.