Optical and magnetooptical properties of Fe/Au multilayers

The optical and magnetooptical properties and transverse Kerr effect (TKE) have been experimentally studied in Fe/Au multilayers with a fixed thickness of Fe layers (t(Fe) = 3 nm) and varied thicknesses of Au layers (t(Au) = 1-3 nm) in an energy range of 0.5-5.0 eV. A comparison of the experimental and model optical and magnetooptical properties of the Fe/Au multilayers shows that transition regions (alloy) 1.7-1.9 nm thick spontaneously form between pure metal layers during their deposition. These regions noticeably affect the optical and magnetooptical properties of the Fe/Au multilayers. The nature of the main features in the optical conductivity and TKE spectra has been established. The experimental TKE spectra of the Fe/Au multilayers exhibit an additional magnetooptical response at homega > 2.5 eV; its nature is related to the spin polarization of the unreacted portions of the gold layers. The off-diagonal components of the permittivity tensor for spin-polarized gold layers are calculated.