The magneto-optical properties of an ensemble of ellipsoidal dielectric particles in a magnetic fluid

The paper deals with an analytical investigation of magnetic birefringence in a dilute suspension of ellipsoidal dielectric particles in a magnetic fluid. The major axes of particles tend to line up along the field because of the difference in the “demagnetizing” coefficients along and across the ellipsoid axis, which brings about a multiple increase in the optical anisotropy of the system. Formulas are derived which describe the field dependence of magnetization of the system and of the difference between the refractive indices for ordinary and extraordinary rays. It is demonstrated that, given the bulk concentration of impurity particles of several percent, the magnetization of the system varies insignificantly, while the birefringence signal may increase by two orders of magnitude.