Physicochemical Interaction and Atomic Structure at Cu-MgO Interfaces

Physicochemical interactions at Cu-MgO buried interfaces are studied by electron X-ray emission spectroscopy and compared to results obtained for native interfaces. The atomic arrangement is also determined. The role of the characteristics of the substrate is evidenced. Results suggest that weak or strong interactions can be present at the interfaces

Depth Profiles of Al/Mn/Si Multilayers

An electron scattering model called IntriX associated to electron X-ray emission spectrometry (EXES) at high resolution is tested to characterize stratified samples. The ability of the model to simulate the X-ray intensity emitted by a surface layer and a buried layer in film/substrate systems is illustrated. The characterization of Al/Mn/Si multilayers by means of non destructive techniques (electron probe microanalysis (EPMA), Rutherford back scattering (RBS)) have been performed comparatively to the EXES measurements. The potentialities of the IntriX model combined to EXES to predict thicknesses is established by comparison with EPMA and RBS results

Compositional Changes at the Early Stages of Nanoparticles Growth in Glasses

International audienc

Compositional changes of phase-separated nanoparticles in silicates

International audience(< 1500 characters): The study of amorphous phase-separated Dielectric Nano-Particles (DNPs) smaller than 10 nm is a great challenge for the materials community. In conjunction with Transmission Electron Microscopy (TEM) and Electron-Probe Micro-Analysis (EPMA), we took advantage of a recent technology, Tri-Dimensional (3D) Atom Probe Tomography (APT) to investigate the variations of the chemical composition in sub-20-nm oxide nanoparticles, grown in silicate glass through heat treatments, at their early stages of nucleation. More precisely, we are investigating the core of an optical fiber drawn from a preform prepared according to the Modified Chemical Vapor Deposition (MCVD) process. We provide here a comprehensive set of experimental data obtained from direct measurements of the concentration for P, Mg, Ge and Er within amorphous dielectric nanoparticles (DNP) of radii ranging from 1 nm to 10 nm. We report on an increase of the concentration of Mg and P with the size of the DNPs. Most importantly, we also demonstrate that erbium ions are partitioned in these small DNPs and their environment changes with the size of the nanoparticles. Molecular dynamics simulations were also implemented to discuss the structural modifications of the Er environment. This presentation highlights the trade off on the size of the DNPs: smaller to reduce light scattering vs bigger to modify luminescence properties

Opaque minerals, magnetic properties, and paleomagnetism of the Tissint Martian meteorite

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