SINGULARITIES IN THE FIELD-DEPENDENCE OF THE MAGNETOOPTICAL KERR-EFFECT IN THIN MAGNETIC SANDWICHES

We consider an antiferromagnetically coupled sandwich consisting of two ferromagnetic transition-metal layers separated by a thin non-magnetic spacer layer, e.g. Fe/Au/Fe. We calculate, using the Kubo formalism, the influence of the angle gamma between the magnetizations in the two ferromagnetic layers on the magneto-optic Kerr effect. Similarly to previously observed oscillations of the magneto-optic Kerr effect as a function of layer thickness, we predict quantum singularities in the Ken signal as a function of gamma, i.e. as a function of the external field. The observation of these singularities would provide further confirmation of the existence of quantum well states in these systems.