3D Monte Carlo simulations on the control of the aggregate structures of cubic magnetic particles in terms of an external electric field

Abstract

We have addressed a suspension composed of magnetic cubic particles, which have a magnetic dipole moment at the particle center magnetized along the diagonal direction of the cube, in order to elucidate the physical phenomenon of the attachment characteristics and the aggregation structure of these particles, by means of Monte Carlo simulations. The cubic particles are negatively charged and confined between the two parallel walls one of which is positively charged (i.e., electrode) and the other is connected to the ground. The main results obtained here are summarized as follows. In the case of no external magnetic field, if the magnetic interaction is sufficiently strong for the formation of stable chain-like clusters, then longer chain-like clusters are formed between the two parallel walls and these clusters are more significantly located along the surface of the electrode as the electric interaction strength is increased. In the case of the electric particle-wall interaction being stronger than the magnetic interaction, almost all constituent cubic particles of chain-like clusters more significantly attach to the surface of the electrode in a face-to-face contact manner between the face of the cube and the wall. To the contrary, if the magnetic interaction is stronger than the electric interaction, the chain-like clusters are formed in the space of the two parallel walls from the end particle attached to the electrode wall. In the case of an external magnetic field applied along the surface of the electrode wall, the chain-like clusters are formed and extended from the surface to the space of the two parallel walls with the end of the particle of the clusters attached to the electrode wall.