title: Two-dimensional Monte Carlo simulations of a colloidal dispersion composed of polydisperse ferromagnetic particles in an applied magnetic field.
abstract: We have investigated aggregation phenomena in a polydisperse colloidal dispersion of ferromagnetic particles simulated by employing the cluster-moving Monte Carlo method in an applied magnetic field. The influence of both particle-particle and particle-field interactions on the aggregate structures is analyzed in terms of a pair correlation function. The results obtained in this study are summarized as follows: Under a strong magnetic field, chainlike clusters are formed along the magnetic field direction, and they become thickly clustered with an increase in the strength of the external magnetic field. Moreover, the thickly clustered chains are formed for a polydisperse system that has a large standard deviation of particle diameters. In contrast, for a very weak magnetic field, the strong interaction between the larger particles gives rise to the formation of various shapes in the chainlike clusters, including bending, looping, and branching. With an increase in the external magnetic field, these structures reorganize to form straight chainlike clusters. Furthermore, the thickness of the chainlike clusters for the polydisperse system is found to depend on the standard deviation of the particle-size distribution but is found to be independent of the magnetic field strength.
authors.affiliation: Department of Machine Intelligence and System Engineering, Faculty of System Science and Technology, Akita Prefectural University, 84-4 Ebinokuchi, Tsuchiya-aza, Honjyo, Akita 015-0055, Japan. aoshima@akita-pu.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Aoshima
authors.forename: Akira
authors.initials: A
authors.lastname: Satoh
mesh_terms: D003102:Colloids / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008280:Magnetics; D009010:Monte Carlo Method; D010316:Particle Size
chemical_list: D003102:Colloids; D007501:Iron