The study of a ferrofluid exhibiting both Brownian and Neel relaxation

Abstract

The low-field complex susceptibility curves of ferrofluids have in general a Debye-type profile with a loss component which peaks at a frequency from which it is possible to estimate the average relaxation time of the particles in the ferrofluid. The authors report on magnetic measurements on a water-based ferrofluid whose loss curve displayed two distinct peaks. It is concluded that one peak is due to Brownian relaxation and the other is due to a combination of Brownian and Neel relaxation.

Enhancement of AC-losses of magnetic nanoparticles for heating applications

“…Refs. [11][12][13]). For instance, Bacri et al [13] measured magneto-optical relaxation in order to determine elastic moduli of gel near the sol-gel transition.…”

Determination of the Size Distribution of Magnetite Nanoparticles from Magnetic Measurements

“…(1). Fannin [20] has assessed the theoretical contribution of the Néel relaxation by weight-averaging the susceptibilities with particle radii distributions obtained from electron microscopy. In the present study, we integrate Eq.…”

Characterisation of magnetic fluids

“…For the particle sizes used in this study, Néel relaxation would be observed in the MHz-GHz region [7]; thus in the frequency range measured here Néel relaxation is considered to be dominant.…”