Optical and magneto-optical properties of multilayer nanosized [Co/TiO$_{2}$]$_{n}$ films

The optical and magneto-optical properties of the metal–dielectric multilayer [Co/TiO$_{2}$]$_{n}$ structures with 2–4-nm-thick layers prepared on a silicon substrate Si(001) by ion-beam deposition have been studied. The complex permittivity of multilayer [Co/TiO$_{2}$]$_{n}$ structures has been measured by the optical ellipsometry technique in the spectral range of 0.6–5.6 eV and analyzed using the optical reflection matrices for isotropic multilayer dielectric structures taking into account the optical losses and also using the method of anisotropic effective medium. The magneto-optical Kerr effect has been measured by the polarimetric technique in the spectral range of 1.2–4.5 eV in the polar and longitudinal geometries. The magnetic anisotropy type is determined on the base of the field dependences of the magneto-optical Kerr effect. It is found that the nanosized [Co/TiO$_{2}$]$_{n}$ structures can be considered as artificial optically uniaxial media with a strong magnetic and optical anisotropy at room temperature.