Epitaxial magnetic layers in transparent matrix are novel nanostructures, which were proposed and made here. Cobalt and CaF2 were grown on Si by molecular beam epitaxy. From reflection high energy electron diffraction images, it was found that epitaxial cobalt films grow on CaF2 in face centred cubic lattice. Magneto-optical Kerr effect was used to study magnetisation of Co films. Change of sign of Kerr rotation and significant increase of its value were observed depending on combination of cobalt and fluoride layer thickness. In-plane magnetic anisotropy was demonstrated in the structures Co/CaF2/Si(0 0 1) with goffered fluoride layer. Combination of magnetic and transparent materials in one structure allows us to control its magnetic and optical properties and observe a variety of magneto-optical effects. (c) 2006 Elsevier B.V. All rights reserved.