INVESTIGATION OF THE NON-LINEAR AND ISOTROPIC PROPERTIES OF MAGNETIC FLUIDS
Pages 1-10
P. C. Fannin
Abstract
Measurement of the frequency dependent, complex susceptibility, χ(ω) = χ' (ω)-i χ"(ω), of magnetic fluids, by means of the toroidal technique, is a well established technique for determining the dynamic properties of magnetic fluids. Here we further demonstrate its usefulness in investigating (1) the non-linear and (2) the isotropic properties of magnetic fluids under the influence of an external polarising field. In the case of a fluids isotropic properties we show how data, obtained from such polarised measurements, in conjunction with the Weierstrass hypothesis, can be used to determine the isotropic properties of a sample. We also show how the magnetic analogue of the non-linear model of Déjardin, may be used to describe the susceptibility spectra of magnetic fluids with values of polarizing fields up to 2,250 A/m.