Eur. Phys. J. E 7, 209-220 (2002)
DOI: 10.1140/epje/i200101129

Dilution series approach for investigation of microstructural properties and particle interactions in high-quality magnetic fluids

M. Rasa^{1, 2}, D. Bica^{2, 3}, A. Philipse¹ and L. Vékás<sup>2, 3

1</sup>  Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8 3584 CH Utrecht, The Netherlands
²  Institute for Complex Fluids, "Politehnica" University of Timisoara, Bd. Mihai Viteazul 1, Timisoara-1900, Romania
³  Center for Fundamental and Advanced Technical Research, Romanian Academy of Science, Timisoara Branch Bd. Mihai Viteazul 24, Timisoara-1900, Romania

m.rasa@chem.uu.nl

(Received 27 August 2001)

Abstract
The aim of the paper is to study the deviation of magnetic properties of the magnetic fluids prepared for this study, from ideal (Langevin) behaviour, i.e. to estimate particle interaction influence and dimensions and influence of particle aggregates, as well as to explain the related effects observed. We also determine the particle coupling parameter, the particle nonmagnetic layer thickness, and the particle distribution, which are fundamental for sample characterization. A comparison of the studied magnetic fluids with each other, with respect to microstructure formation and particle interaction strength is finally done. For these purposes, a concentration dependence study, following the proposed "dilution series approach", is performed. Three series of dilutions of three types of magnetic fluids were prepared and analyzed.

PACS
75.50.Mm - Magnetic liquids.
75.60.Ej - Magnetization curves, hysteresis, Barkhausen and related effects.
82.70.Dd - Colloids.


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002