Resonant magnetic reflectivity from U/Fe multilayers

Abstract

U/Fe multilayers have been produced through dc sputtering. The high quality of these multilayers has been confirmed through x-ray reflectivity measurements and fitting to the resultant spectra. These samples are currently the subject of investigations using techniques including polarized neutron reflectivity, conversion electron Mössbauer spectroscopy, and magnetotransport and magneto-optic measurements. In this article, we report on results obtained from a [U 30 Å/Fe 40 Å]×30 multilayer through resonant magnetic scattering performed on the XMaS beamline at the European Synchrotron Radiation Facility. The asymmetry ratio is defined as (I+−I−)/(I++I−), where I+(I−) is the normalized intensity obtained with circular polarization and the applied field parallel (antiparallel) to the beam direction. Asymmetry data are presented as functions of both energy and momentum transfer. We have identified a Uranium moment with the use of resonant magnetic reflectivity at 12 K. Reversal of the polarity of the asymmetry ratio between the first and second superlattice peaks indicates a nonuniform moment distribution through the uranium layers. Temperature dependence measurements confirm that the moment also exists at room temperature.