Peculiarities of the magneto-optical response in dispersions of anisometric pigment nano-particles

Abstract

We demonstrate an unusually strong magneto-optical response of elongated plate-shaped pigment particles in magnetic fields ranging from 0 to 25 T. In a weak field, the particles align perpendicular to the field and the dispersions exhibit the Cotton–Mouton effect. In a strong magnetic field, the magneto-optical behaviour is nonlinear and cannot be explained by a simple model of non-interacting diamagnetic rods in a thermal equilibrium. We also demonstrate that the addition of a small amount of magnetic particles results in a complex magneto-optical response, where the particles align parallel to a weak magnetic field and perpendicular to a strong one.