Influence of dipolar interactions on the magnetic susceptibility spectra of ferrofluids / Sindt Julien O.,Camp Philip J.,Kantorovich Sofia S.,Elfimova Ekaterina A.,Ivanov Alexey O. // PHYSICAL REVIEW E. - 2016. - V. 93, l. 6.

ISSN/EISSN:

2470-0045 / 2470-0053

Type:

Article

Abstract:

The frequency-dependent magnetic susceptibility of a ferrofluid is calculated under the assumption that the constituent particles undergo Brownian relaxation only. Brownian-dynamics simulations are carried out in order to test the predictions of a recent theory {[}A. O. Ivanov, V. S. Zverev, and S. S. Kantorovich, Soft Matter 12, 3507 (2016)] that includes the effects of interparticle dipole-dipole interactions. The theory is based on the so-called modified mean-field approach and possesses the following important characteristics: in the low-concentration, noninteracting regime, it gives the correct single-particle Debye-theory results; it yields the exact leading-order results in the zero-frequency limit; it includes particle polydispersity correctly from the outset; and it is based on firm theoretical foundations allowing, in principle, systematic extensions to treat stronger interactions and/or higher concentrations. The theory and simulations are compared in the case of a model monodisperse ferrofluid, where the effects of interactions are predicted to be more pronounced than in a polydisperse ferrofluid. The susceptibility spectra are analyzed in detail in terms of the low-frequency behavior, the position of the peak in the imaginary (out-of-phase) part, and the characteristic decay time of the magnetization autocorrelation function. It is demonstrated that the theory correctly predicts the trends in all of these properties with increasing concentration and dipolar coupling constant, the product of which is proportional to the Langevin susceptibility chi(L). The theory is in quantitative agreement with the simulation results as long as chi(L) less than or similar to 1.

Author keywords:

MEAN-FIELD THEORY; ROTATIONAL DIFFUSION; THERMAL FLUCTUATIONS; HARD-SPHERES; NANOPARTICLES; FERROCOLLOIDS; HYPERTHERMIA; RELAXATION; PARTICLES; MEDIATORS

DOI:

10.1103/PhysRevE.93.063117

Web of Science ID:

ISI:000378376600010

Соавторы в МНС:

Другие поля

Поле	Значение
Month	JUN 24
Publisher	AMER PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	063117
EISSN	2470-0053
Keywords-Plus	MEAN-FIELD THEORY; ROTATIONAL DIFFUSION; THERMAL FLUCTUATIONS; HARD-SPHERES; NANOPARTICLES; FERROCOLLOIDS; HYPERTHERMIA; RELAXATION; PARTICLES; MEDIATORS
Research-Areas	Physics
Web-of-Science-Categories	Physics, Fluids \& Plasmas; Physics, Mathematical
Author-Email	philip.camp@ed.ac.uk
ResearcherID-Numbers	Elfimova, Ekaterina/P-5003-2016 Ivanov, Alexey/E-4442-2011 Kantorovich, Sofia/H-4586-2011
ORCID-Numbers	Ivanov, Alexey/0000-0001-8239-4039 Kantorovich, Sofia/0000-0001-5700-7009 Camp, Philip/0000-0002-7901-1364 Elfimova, Ekaterian/0000-0002-8941-8184
Funding-Acknowledgement	Engineering and Physical Sciences Research Council (U.K.); Russian Science Foundation {[}15-12-10003]
Funding-Text	J.O.S. was supported by a studentship from the Engineering and Physical Sciences Research Council (U.K.). S.S.K., E.A.E., and A.O.I. gratefully acknowledge research funding from the Russian Science Foundation (Grant No. 15-12-10003). J.O.S., P.J.C., and E.A.E. thank the Ural Federal University for supporting collaborative visits between Edinburgh and Ekaterinburg.
Number-of-Cited-References	51
Usage-Count-Last-180-days	3
Usage-Count-Since-2013	14
Journal-ISO	Phys. Rev. E
Doc-Delivery-Number	DP3EX