The polarized neutron reflectivity and X-ray reflectivity studies of the magnetic profiles of epitaxial Ni80Fe20/Ru multilayers

The depth profiles of the epitaxial Ni80Fe20(1 1 1)/Ru(0 0 0 1) multilayers were studied by polarized neutron reflectivity and X-ray reflectivity. At the Ru thickness that the anti-ferromagnetic coupling was found, the magnetic moments between two Ni80Fe20 interlayers show a biquadratic coupling effect with a double unit cell at low applied fields. A magnetic dead layer of about 0.3 nm was also found at the interface boundaries. The maximal polarization effect applied to the Ru layer is less than 0.03μB.