Features of magnetorefractive effect in a [CoFe/Cu]$_{n}$ multilayer metallic nanostructure

The features of magnetorefractive effect (MRE) in metallic multilayer film Ni$_{48}$Fe$_{12}$Cr$_{40}$(50 $\mathring{\mathrm{A}}$)/[Co$_{90}$Fe$_{10}$(14 $\mathring{\mathrm{A}}$)/Cu(22 $\mathring{\mathrm{A}}$)]$_{8}$/Cr(20 $\mathring{\mathrm{A}}$) nanostructures, which exhibit giant magnetoresistance at room temperature, are investigated experimentally and theoretically. We show that the MRE in these structures reaches 1.5% in an applied magnetic field of 3.5 kOe, in a broad part of the IR region, and can change sign for both transmission and reflection of light. The refraction and extinction coefficients that are calculated for the nanostructures in an external magnetic field are in good agreement with our experimental data. The deduced formulas can be applied to estimating the MRE in multilayer metallic nanostructures.