X-ray resonant magnetic scattering experiments using linear and circular polarized light were performed at the Ni Lz3 absorption edges on a Ag/Ni multilayer.A superlattice magnetic peak, due to the antiferromagnetic coupling between Ni layers, is evidenced. In the case of a ferromagnetic coupling, large changes in the charge peak (up to 15%) are observed upon reversal of the direction of the magnetic field. The magnetic scattering amplitude is evaluated to SI. O per nickel atom. Sum rules have been applied for the first time to the energy-dependent magnetic amplitude.
The local structure of As Te&00 glassy semiconductors has been studied using x-ray anomalous scattering and x-ray-absorption spectroscopy as a function of the composition. Two important findings are (a) tellurium (Te) atoms are twofold coordinated in arsenic (As) rich alloys (x )40), while the Te coordination suddenly increases to 2.4 at the stoichiometric As40Te«composition, which indicates a large fraction (about 50%) of threefold Te sites in this glass. This percentage of occupancy of the threefold Te sites remains almost constant with increasing further the Te concentration; (b) a significant level of chemical disorder, marked by the existence of homopolar As-As and Te-Te pairs in the first coordination shell, is observed for all the investigated glasses. At the As4OTe«composition, nearly about the same amount of As-As and Te-Te pairs do exist in the first coordination shell. Thus the stoichiometric As4OTe«composition is not a chemical threshold as it is the case for the Seor S-based glasses. Based on these results, a number of peculiar and unique features in the physical properties of these glasses, such as the glass transition temperature (Tg) the microhardness, the glass forming ability, and the electrical conductivity, can be understood.
The element and electronic shell selectivity of x-ray resonant magnetic scattering ͑XRMS͒ has been used to investigate the profile of the spin polarization of the 5d electronic states of Ce and La across the rare-earth layers in Ce/Fe and La/Fe multilayers. The magnetic contributions to the diffracted intensities have been measured at low angles, at the L 2 edge of the rare earth. In agreement with previous results from x-ray magnetic circular dichroism ͑XMCD͒ experiments, the La 5d polarization is found to be localized right at the interfaces with the Fe layers, as it is expected from a direct hybridization with the Fe 3d states. In the case of Ce/Fe multilayers where Ce is in an ␣-like electronic state with a complex behavior of the 5d magnetic polarization, the XRMS results obtained for two samples with 10 and 22 Å thick Ce layers indicate that the Ce 5d polarization decreases slowly from the interfaces towards the center of the layers. This is in agreement with previous XMCD results. However, at least for the two samples which have been investigated, XRMS also suggests that the Ce 5d polarization oscillates across the Ce layer with a period equal to the ͑111͒ interplanar distance in ␣ fcc Ce. Though compatible with the XMCD findings, this oscillating behavior cannot be derived from its dependence on the Ce layer thickness because of the decrease of the magnetic polarization which prevents us from observing changes in the sign of the XMCD amplitude. ͓S0163-1829͑99͒04637-8͔ PHYSICAL REVIEW B 1 OCTOBER 1999-I VOLUME 60, NUMBER 13 PRB 60 0163-1829/99/60͑13͒/9662͑13͒/$15.00 9662
Interest in the use of soft X-ray resonant magnetic scattering techniques to probe the distribution of magnetic moments in thin films has exploded during the last few years. In this paper a novel diffractometer devoted to temperature-dependent soft X-ray resonant scattering is described. The principal features of the diffractometer are presented and illustrated through experiments performed at LURE during the commissioning phase.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.