0000000000768775
AUTHOR
Yves Mathey
Nanoscale x-ray absorption spectroscopy using XEOL-SNOM detection mode
The first results obtained with the prototype system at the synchrotron beamline ID03 at ESRF are presented and illustrate the possibility to detect an element-specific contrast and to perform nanoscale x-ray absorption spectroscopy experiments at the Zn K and W L 3 absorption edges in mixed zinc oxide-zinc tungstate thin films.
XAS, XRD, AFM and Raman studies of nickel tungstate electrochromic thin films
Abstract Systematic studies of nanocrystalline nickel tungstate, NiWO 4 , thin films were performed by several experimental techniques such as Ni K- and W L 1,3 -edges X-ray absorption spectroscopy, X-ray diffraction, Raman spectroscopy, atomic force microscopy and cyclic voltammetry measurements. We found that the NiWO 4 thin films exhibit electrochromic properties similar to that of amorphous tungsten trioxide films, but show better structural stability upon multiple colouring/bleaching cycling. It was observed that a nanocrystallinity of the thin films results in strong modifications of the NiO and WO interactions, which affect both local atomic and vibrational structures.
XAFS studies of local atomic structure of niobium tellurides
Abstract We present XAFS (K-edge) studies of the local atomic structure around the Nb and Te ions in niobium tellurides (NbTe 2 , Nb 3 Te 4 and NbTe 4 ) in comparison with ZrTe 2 . Using a multi-shell best-fit analysis procedure, we have reconstructed local environments of the Nb and Te ions and compared them with the existing structural models. We found that at the Nb K-edge the XAFS data of NbTe 4 are extremely sensitive to metal clustering and to the subsequent departure from the average crystallographic positions. Moreover, at the Te K-edge the XAFS data allowed us to distinguished the different type of TeTe bonds, for instance: the dimer (TeTe: 2.9 A) and the squares (TeTe: 3.3 A) i…