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A NEW METHOD FOR DETERMINATION OF THE EFFECTIVE ANISOTROPY CONSTANT OF THE PARTICLES WITHIN FERROFLUIDS

I. Mãlãescu1,*

Affiliation

  1. West University of Timisoara, Faculty of Physics, Dept. of Electricity and Magnetism, Bd. V. Parvan no. 4, 1900 Timisoara, Romania

Abstract

A new method for determination of the effective anisotropy constant (magnetocrystalline, shape and surface), Keff, of the colloidal particles within ferrofluids, from ferromagnetic resonance measurements and based on the theoretical values computed for the Lande factor (g) of the ferrite molecule, is described. Two ferrofluids samples (denoted F1 and F2), with magnetite particles dispersed in kerosene and stabilized with oleic acid, were used. In the proposed method only one measurement (magnetic resonance) is necessary in order to determine Keff. The Lande factor of the magnetite molecule, having the chemical formula,  + −   +  2−3322 2 Fe O Fe OA B, was computed that the weight mean value of the Landé factors corresponding to the three ions in the tetrahedral positions (A) and in the octahedral positions (B). The values obtained in this way for Keff are compared to the ones determined from other measurements..

Keywords

Ferrofluids, Effective anisotropy constant, Magnetic resonance.

Submitted at: July 22, 2002
Accepted at: March 12, 2003

Citation

I. Mãlãescu, A NEW METHOD FOR DETERMINATION OF THE EFFECTIVE ANISOTROPY CONSTANT OF THE PARTICLES WITHIN FERROFLUIDS, Journal of Optoelectronics and Advanced Materials Vol. 5, Iss. 1, pp. 233-237 (2003)