Thickness- and morphology dependence of the optical and magneto-optical properties of CrPt3 films

The use of magnetic films for applications as magneto-optical storage media requires, among other properties, perpendicular magnetic anisotropy. This can be achieved sometimes by an epitaxial or textured growth, sometimes by a columnar growth of polycrystalline or amorphous films, and sometimes by a reduction of the film thickness so as to enhance the effect of surface anisotropy. The optical and magneto-optical properties of epitaxial films grown by MBE on (001)-oriented SrTiO3 substrates have been investigated. Wedge shaped as well as plane-parallel films were prepared to differentiate between incoherent and coherent interference effects. It is shown that the morphology influences strongly the normal optical constants and less the magneto-optical Kerr signal, while coherent interference effects affect the Kerr signal as much. Quantitative fits using effective medium and matrix models are presented.