Dresden 2006 – scientific programme
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.116: Poster
Thursday, March 30, 2006, 16:00–18:00, P1
Equilibrium Properties of a Bidispersed Ferrofluid with Chain Aggregates: Theory and Computer Simulations — •Christian Holm1,2, Sofia Kantorovich3, Alexei O. Ivanov3, and E.S. Pyanzina3 — 1Frankfurt Institute for Advanced Studies (FIAS) Johann Wolfgang Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany — 2Max-Planck-Institut für Polymerforschung, Ackermannweg 10, D-55128 Mainz, Germany — 3Urals State University, Lenin av, 51, Ekaterinburg, 620083, Russia
The presence of chains, formed due to the magnetic dipole-dipole interaction, leads to strong deviations of magnetization curve from the Langevine curve for ideal superparamagnetic gas. Here we compare simulational results for a bidisperse ferrofluid (Ref. [2]) with the theoretical model (bidisperse ferrofluid with chains) predictions (Ref. [3]). We find for a small concentration of the large particle that the magnetization behavior is close to the one given by the modified mean field approach. For higher concentration of large particles there is a considerable growth in the initial susceptibility. The latter cannot be described in terms of homogeneous ferrocolloids. Using the results of Ref [1,3] we built a bidisperse model and calculated magnetic and structural quantities of the bidisperse fluid of Ref. [2]. The theoretical results are in excellent quantitative agreement with the ones of computer simulations.
[1] V.S. Mendelev, A.O. Ivanov, Physical Review E 70, 051502 (2004)
[2] Z. Wang, C. Holm, Physical Review E 68, 041401 (2003)
[3] S.S.Kantorovich, A.O. Ivanov, Physical Review E 70, 021401 (2004)