Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 14: Topical Session Nanoanalytics using Small-Angle Scattering II

MM 14.1: Hauptvortrag

Dienstag, 24. März 2009, 11:45–12:15, IFW A

Anomalous small-angle X-ray scattering in material science — •Armin Hoell — Helmholtz-Zentrum Berlin für Materialien und Energie, Glienicker Strasse 100, 14109 Berlin, Germany.

Anomalous small-angle X-ray scattering (ASAXS) is an element-selective method based on the anomalous variation of the atomic scattering factor near absorption edges. Nowadays, ASAXS is a mature technique to analyse nano-structures as well as their chemical composition fluctuation. It is used in physics, chemistry, biology and soft / hard condensed matter. This talk will elaborate the advantages of ASAXS in the analysis of complex materials. In the first part important technical details and strategies to measure ASAXS will be emphasized. In the second part some material science applications are chosen to illustrate different aspects and benefits of ASAXS. While using the relative contrast variation between SAXS curves measured at different energies near below absorption edges of elements containing in the sample the composition fluctuations are derived in a demixed supercooled liquid state of a ZrTiCuNiBe alloy. The method of partial structure functions derived from ASAXS will be explained by way of the example of an AlNiLa alloy. So, in case of Ruthenium/Selenium based catalysts ASAXS allows to determine characteristic length-scales associated with three different structural elements. Furthermore, it will be shown how a simultaneous nonlinear regression method including physical constrains can be used to resolve the nano-structure of a silver-free photochromic glass.