Enhancement of polar Kerr rotation in Fe/Al2O3 multilayers and composite systems

We present theoretical and experimental results on the magneto-optic polar Kerr effect relative to several composite systems based on simple iron layers associated with amorphous alumina. The systems studied are either multilayers with a variable number of periods or trilayers. We have investigated the effect of the number of periods and of the individual layer thicknesses in the case of multilayers. Concerning trilayers, the role of the thickness of individual layers and of the stacking sequence is shown. We demonstrate that we can obtain very large values of Kerr rotation by optimization of the samples. A Kerr rotation close to 20 degrees is, for instance, obtained with a very simple trilayer system: alumina/iron/alumina/Si substrate. [S0163-1829(99)01617-3].