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Investigation of magnetic fluids exhibiting field induced absorption peaks in the susceptibility spectra

P. C. FANNIN1,* , C. MAC OIREACHTAIGH1, I. ML ESCU2, C. N. MARIN2

Affiliation

  1. Department of Electronic and Electrical Engineering, Trinity College, Dublin 2, Ireland
  2. West University of Timisoara, Faculty of Physics, Dept. of Electricity and Magnetism, Bd. V. Parvan #4, 1900 Timisoara, Romania

Abstract

Measurements of the frequency and field dependent of the complex magnetic susceptibility, χ(ω, Η)= χ'(ω,Η) - iχ''(ω, Η) , of magnetic fluids over the frequency range, 200Hz to 1 MHz, by means of the toroidal technique, are presented. The magnetic polarizing field, H, is increased from 0 to 13.6 kA/m in fifteen steps and the resulting susceptibility spectra is found to exhibit a field induced , double loss-peak over the frequency range concerned. The existence of a double absorption peak is quite unusual and represents a double or bi-modal distribution of particles sizes in the ferrofluid sample. The equations of Debye are used to determine corresponding aggregate radii whilst a measure of a distribution of relaxation times is obtained in terms of the Cole-Cole distribution parameter, α..

Keywords

Magnetic fluid, Susceptibility spectra, Debye equations.

Submitted at: Oct. 14, 2005
Accepted at: Jan. 26, 2006

Citation

P. C. FANNIN, C. MAC OIREACHTAIGH, I. ML ESCU, C. N. MARIN, Investigation of magnetic fluids exhibiting field induced absorption peaks in the susceptibility spectra, Journal of Optoelectronics and Advanced Materials Vol. 8, Iss. 1, pp. 46-49 (2006)