Use of the Longitudinal Magneto-optical Kerr Effect to Study Nonmagnetic/Magnetic Bilayers

We report the results of Longitudinal Magnetooptical Kerr Effect (LMKE) measurements on bilayers consisting of a thick permalloy film covered by varying thicknesses of the non-magnetic metal Nb. The technique gives experimental information (a) on the magnetic properties of films bounded on both sides by non- magnetic material rather than the usual asymmetric case of substrate on one side and exposed surface on the other; and (b) on the phase and intensity of the optical frequency electric field below a reflecting surface.