On the utility of low frequency, polarised, complex susceptibility measurements in the investigation of the dynamic properties of magnetic fluids

Abstract The measurement of the field and frequency-dependent, complex susceptibility, χ (ω, Η) = χ′(ω, H) − iχ″ (ω, Η), is an established method for investigating the dynamic properties of magnetic fluids. Polarised measurements have been used to investigate many properties of magnetic fluids, including, relaxation mechanisms, aggregation, magnetic losses, loss factor tanδ, power factor sinδ, and the influence which polarising fields may have on the hysteresis and isotropic properties of samples. In this paper, a review is given of these topics and typical results are presented.