Anisotropic third-order magneto-optical Kerr effect

The magnitude of the polar magneto-optical Kerr effect in reflection from thick iron epitaxial films is experimentally found to strongly depend on the crystallographic orientation of the film, with variations of more than 20%. Similar results are obtained on the (001) and (110) faces of a bulk Fe crystal. It is shown that this anisotropy can be described as a third-order effect in the magnetization M on the optical response epsilon(omega,M). Our analysis can also be used to understand the transversal Kerr effect at normal incidence recently observed by Gridnev et al. (C) 1998 American Institute of Physics. [S0021-8979(98)46611-8].