WAVELENGTH DEPENDENCE OF THE FARADAY-EFFECT AND MAGNETOBIREFRINGENCE IN FERROFLUID THIN-FILMS

An enhancement of negative Faraday rotation in a dilute ferrofluid was reported near the wavelength of 0.5 mum by Yusuf. The observed phenom enon was explained in terms of a ''small particle resonance.'' The pre mise of the above explanation is debatable. In order to give a more de tailed explanation, measurements of Faraday rotation and magnetobirefr ingence spectra in dense ferrofluid thin films are reported from 0. 5 to 2.7 mum, and a mathematical model is derived taking into account a skew-symmetric dielectric tensor for ferrite particles. The experiment s confirm that the negative Faraday rotation is predominantly caused b y the wavelength dependence of the off-diagonal elements epsilon(f)xy/ (lambda) of the dielectric tensor of the magnetic particles themselves .