Magnetic field induced increase of the longitudinal Kerr effect in multilayer Co∕Cu(111) films

A many-fold increase of the longitudinal Kerr effect in a magnetic field has been found in multilayer Co∕Cu(111) films for definite thicknesses of the copper layers, which give extrema of the exchange coupling between the cobalt layers. It is conjectured that this phenomenon is due to the presence of a large contribution of the Co/Cu interfaces to the magneto-optic effect and is due to the paramagnetism of the conduction electrons in the interface layers, increased by hybridization of the electronic sp and d bands of copper and cobalt. It is conjectured that the periodic increase of the magneto-optic susceptibility is due to the sensitivity of the hybridization to the quantization of the transverse motion of the electrons in the copper layers.