The effects of polydispersity on the initial susceptibilities of ferrofluids / Camp Philip J.,Elfimova Ekaterina A.,Ivanov Alexey O. // JOURNAL OF PHYSICS-CONDENSED MATTER. - 2014. - V. 26, l. 45.

ISSN/EISSN:

0953-8984 / 1361-648X

Type:

Article

Abstract:

The effects of particle-size polydispersity on the initial susceptibilities of concentrated ferrofluids are analyzed using a combination of theory and computer simulation. The study is focused on a model ferrofluid with a prescribed magnetic-core diameter distribution, a fixed non-magnetic surface layer (corresponding to a demagnetized layer and adsorbed surfactant) and a combination of dipolar and hard-core interactions. The non-trivial effects of polydispersity are identified by comparing the initial susceptibilities of monodisperse and polydisperse ferrofluids with the same Langevin susceptibility. The theory is based on a correction to the second-order modified mean-field theory arising from a formal Mayer-type cluster expansion; this correction is dependent on a parameter similar to the normal dipolar coupling constant, except that it contains a complicated double average over the particle-size distribution, which means that the initial susceptibility should depend significantly on polydispersity. Specifically, the theory predicts that the initial susceptibility is enhanced significantly by polydispersity. This prediction is tested rigorously against results from Monte Carlo simulations and is found to be robust. The qualitative agreement between theory and simulation is already satisfactory, but the quantitative agreement could be improved by a systematic extension of the cluster expansion. The overall conclusion is that polydispersity should be accounted for carefully in magnetogranulometric analyses of real ferrofluids.

Author keywords:

ferrofluids; polydispersity; magnetic susceptibility; theory; simulation DIPOLAR HARD-SPHERES; CONCENTRATED FERROCOLLOIDS; FLUID

DOI:

10.1088/0953-8984/26/45/456002

Web of Science ID:

ISI:000343796200016

Соавторы в МНС:

Другие поля

Поле	Значение
Month	NOV 12
Publisher	IOP PUBLISHING LTD
Address	TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Language	English
Article-Number	456002
EISSN	1361-648X
Keywords-Plus	DIPOLAR HARD-SPHERES; CONCENTRATED FERROCOLLOIDS; FLUID
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
Author-Email	philip.camp@ed.ac.uk ekaterina.elfimova@urfu.ru alexey.ivanov@urfu.ru
ResearcherID-Numbers	Elfimova, Ekaterina/P-5003-2016 Ivanov, Alexey/E-4442-2011 lotfollahi, zahra/A-6419-2015
ORCID-Numbers	Ivanov, Alexey/0000-0001-8239-4039 Camp, Philip/0000-0002-7901-1364 Elfimova, Ekaterian/0000-0002-8941-8184
Funding-Acknowledgement	Ministry of Education and Science of the Russian Federation {[}3.12.2014/K, 02.A03.21.0006]; Russian Foundation for Basic Research {[}13-01-96032-r-ural]
Funding-Text	The research was carried out with the financial support of the Ministry of Education and Science of the Russian Federation (Project 3.12.2014/K and Agreement 02.A03.21.0006) and was also partly supported by the Russian Foundation for Basic Research (Grant No. 13-01-96032-r-ural).
Number-of-Cited-References	35
Usage-Count-Last-180-days	1
Usage-Count-Since-2013	14
Journal-ISO	J. Phys.-Condes. Matter
Doc-Delivery-Number	AR7ZT