Photonic Hall effect in ferrofluids: Theory and experiments

An experimental and theoretical study on the photonic Hall effect (PHE) in liquid and gelled samples of ferrofluids is presented. The ferrofluids are aqueous colloidal suspensions of Fe2CoO4 particles, which can be considered as anisotropic and absorbing Rayleigh scatterers. The PHE is found to be p roduced by the orientation of the magnetic moments of the particles, as is also the case for the Faraday effect. The dependence of the PHE with respec t to the concentration of the scatterers, the magnetic field, and the polar ization of the incident light is measured in liquid and in gelled samples, and is compared to a simple model based on the use of a scattering matrix a nd the single scattering approximation.