3D Monte Carlo Simulations of Aggregate Structures in a Magnetic Colloidal Suspension Composed of Plate-Like Particles With Magnetic Moment Normal to the Particle Axis

We have investigated the internal aggregate structures of a colloidal suspension composed of magnetic plate-like particles with a magnetic moment normal to the particle axis by means of three-dimensional Monte Carlo simulations. In concrete, we have attempted to clarify the influences of the magnetic field strength, magnetic interactions between particles, and volumetric fraction of particles, on particle aggregation phenomena. In order to discuss quantitatively the aggregate structures of particles, we have focused on the radial distribution and orientational pair correlation function. For no applied magnetic field cases, long column-like clusters are formed as magnetic particle-particle interactions increase. Characteristics of these clusters are that particles incline in a certain direction with their magnetic moments alternating in direction between the neighboring particles. For applied magnetic field cases, the magnetic moments of the particles incline in the magnetic field direction, so that the columnar clusters are not formed. The brick wall-like aggregates are formed as the influences of the magnetic field and magnetic particle-particle interactions become significantly dominant.