The magneto-optical Kerr effect (MOKE) is a well established technique to study magnetization properties. The effect is based on the fact, that the plane of polarization of light is rotated when the light is reflected from a magnetic material. The physical origin of MOKE is the magnetic circular dichroism effect: exchange and spin-orbit coupling in a magnetic material lead to different absorption spectra for left- and right-circularly polarized light. Measuring the change of the polarization of the reßected beam (often referred to as Kerr angle ΘKerr) gives access to the magnetization state of the sample.