New intensity magneto-optical effect in materials exhibiting giant magnetoresistance

The change in the reflectivity of a metallic magnetic multilayer that exhibits giant magnetoresistance for a monochromatic electromagnetic plane wave with polarization along the magnetization (s polarization! in response to a change from the antiferromagnetic magnetic configuration of the multilayer to the ferromagnetic configuration is investigated. This magneto-optical effect is treated in the effective-medium approximation, in which the dielectric constant needed is found analytically with consideration of the interface roughness scattering of electrons. It is shown in the example of an Fe/Cu multilayer that the effect amounts to similar to 0.7%. The representation found for the complex conductivity is convenient in a special case for investigating the magnetoresistive effect. (C) 1998 American Institute of Physics. [S1063-7761(98)02409-3].