Determination of inhomogeneous magnetic profiles in an asymmetric Fe/Gd multilayer

We have studied the dependence of the detailed magnetization depth profile in a [Fe(35 A)/Gd(50 A)]$_{5}$ multilayer on the applied magnetic field and temperature. Utilizing the complementarity of x-ray resonant magnetic reflectivity (element-specificity and high spatial resolution) and polarized neutron reflectivity (large magnetic scattering cross sections), we applied a unified approach by simultaneous refinement and resolved the complex magnetization profiles. It was found that the small number of periods together with the asymmetric termination (Fe-top, Gd-bottom) lead to unique inhomogeneous magnetic phases, which are characterized by significant twisting of Fe and Gd magnetic moments and non-uniform distribution of magnetization density within the Gd layers.