Magneto-optic depth sensitivity to local magnetization in a simple ultrathin film structure

Starting from experimental results, we show how polar magneto-optics are able to probe the magnetization depth profile at a nanometer scale. This is demonstrated in a simple ultrathin film system built from two magnetic Co layers with perpendicular anisotropy, separated by a non-magnetic Au spacer layer. The individual magnetic contributions of the two ultrathin Co layers may be fully separated when performing Kerr ellipticity measurements at appropriate photon energies. A simple model that takes into account separately the two Co layer contributions to magneto-optical effects is presented. An extension of this treatment to Co/Au multilayers is proposed.