MAGNETOOPTICAL EFFECTS IN FERROFLUIDS AT NEAR MILLIMETER WAVELENGTHS

The results of experiments aimed at establishing the origin of near mi llimetre wavelength magneto-optical effects observed in various ferrof luids are presented and discussed. These microscopic effects are probe d at the macroscopic level by using an a.c. magnetic field to impose p olarization modulation on near millimetre wave radiation propagating t hrough such fluids. The results indicate that the basic mechanism is N eel rotation of the magnetic moment within each component magnetic par ticle of the fluids.