Optical and magneto-optical properties of sputter-deposited Co/Cu multilayers

The optical constants of Co/Cu multilayers have been determined by spectroscopic ellipsometry in the photon energy range 1.4-3.8 eV. The data have been compared with a single-equivalent-layer model based on the optical constants of the constituent materials Co and Cu. In order to explain the detailed spectra, it has been found necessary to modify the optical constants of the copper layers as a result of increased scattering at the interfaces. This effect is taken into account through a modified relaxation time term that appears in the semi-classical dispersion theory for metals. The conclusions based on the optical observations have been confirmed through a comparison between calculated first-order magnetooptical polar Kerr effects and independently measured data obtained from another laboratory.