Magneto-optic polar Kerr and Faraday effects in magnetic superlattices

Magneto-optic (MO) effects in magnetic multilayers with periodic regions ar e discussed assuming normal incidence of polarized waves and polar magnetiz ation (Faraday and polar Kerr effects). From the (4 x 4)-matrix formalism s implified analytical expressions linear in the off-diagonal permittivity te nsor element are obtained with no loss in accuracy. The MO effects are expr essed as weighted sums of contributions from individual layers. Approximate expressions are given for the case when the thickness of magnetic layers i s much smaller than the radiation wavelength. The procedure is illustrated on superlattices consisting of symmetric sandwiches of ultrathin magnetic a nd non-magnetic metallic layers.