Behavior of a system of uniaxial ferroparticles in a rotating liquid matrix

Abstract

Behavior of a system of single-domain ferromagnetic particles with easy-magnetization-axis-type magnetic anisotropy in a rotating fluid matrix is considered in a transverse magnetic field that is weak compared to the effective magnetic anisotropy field of a particle. The dynamics of a separate particle and orientational state of the system are considered with regard for Brownian rotational diffusion. It is found that a small deviation from the conventional rigid dipole model leads, at frequencies exceeding a certain critical value, to appearance of two attracting stationary states of the easiest magnetization axis that are situated in the plane perpendicular to the field and approach, with the growth of a particle, one or another direction of the matrix rotation axis. It is shown that this circumstance can radically change the behavior of a system of Brownian particles and, thus, magnetic and hydrodynamic properties of the ferrosuspension.