Eur. Phys. J. E 6, 399-407 (2001)
Cluster structure and the first-order phase transition in dipolar systems
Monte Carlo simulation
A.F. Pshenichnikov and V.V. MekhonoshinInstitute of Continuous Media Mechanics UB RAS, 1, Korolyev str., 614013, Perm, Russia pshenichnikov@icmm.ru
(Received 27 April 2001 and Received in final form 23 October 2001)
Abstract
The Monte Carlo technique is used to simulate a 3D dipolar hard-sphere system.
The spatial and magnetic structure of clusters
formed by magnetic dipolar interactions in zero applied field is
investigated. It is shown that the many-particle clusters are
characterized by a quasi-spherical shape, extremely small
magnetic moments, and a fractal dimension close to three. These
clusters are regarded as nuclei of a new concentrated isotropic
phase. The numerical simulation of the first-order phase transition
has been realized which allows us to find the interface between
two coexisting phases. It has been found that the dipole-dipole and
steric interactions are sufficient to separate the system into two
phases with low and high concentrations of particles. The
introduction of any additional attraction potential is not
required. The phase diagram of dipolar system in zero applied field
has been obtained. The simulation results are in qualitative
agreement with the predictions of some analytical models.
75.50.Mm - Magnetic liquids.
64.70.Fx - Liquid-vapor transitions.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
