OXIDE NANO-LAYERS STUDIED BY X-RAY RAMAN SCATTERING IN TOTAL REFLECTION GEOMETRY

J. J. LEANI; H. J. SÁNCHEZ; C. A. PÉREZ

Congreso; LNLS User Meeting 2013; 1013

Di®erent processes could take place from the interaction of X-ray with matter: pho- tons can be absorbed by the photoelectric e®ect and decay in °orescence process, the photons could also experience coherent or incoherent scattering. Nevertheless, under resonant conditions, another low probability interaction can occur: the x-ray resonant Raman scattering (RRS) [1]. If the angle of the incident radiation is less than a critical angle derived from the Snells law, X-rays are totally re°ected due to the refractive index is less than unity [2]. Making use of this fact, di®erent depths of a sample can be studied scanning the incident photon angle through this critical angle. At this respect, studies of characteristic emissions, or re°ected intensities, present a tool for the analysis of surface properties, such as variations of electron density with depth with resolutions from ngstrÄoms to microns [3]. This work shows experimental results of X-ray Raman scattering at grazing incidence conditions with the aim of recognize chemical environments in di®er- ent layers of strati¯ed materials using a low resolution energy dispersive system. Multilayer samples of Fe compounds were measured in the XRF beamline of the Brazilian synchrotron facility using monochromatic radiation and an EDS setup. The measurements were performed in total re°ection regime with incident photon energy lower and close to the K absorption edge of Fe. After a simple data processing, the result allowed characterizing oxide nano- layers, not observable with the use of conventional geometries, reaching identi¯ca- tion of the oxidation state present in a particular depth of a sample surface with nanometric, or even sub-nanometric, resolution using a low-resolution EDS system.