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MM: Fachverband Metall- und Materialphysik

MM 48: Topical session: X-ray and neutron scattering in materials science I - Coherent X-ray Diffraction Imaging of Excitations in Metal Nanoparticles

MM 48.2: Vortrag

Donnerstag, 3. April 2014, 10:30–10:45, BAR 205

Static atomic displacements of Fe-27 at.% Pt in the Invar regime — •Cédric Sax and Bernd Schönfeld — LMPT, Department of Materials, ETH Zurich

X-ray diffuse scattering from a single crystalline Fe-27.1 at.% Pt Invar alloy was measured at room temperature and close to the Curie temperature. The sample was set up in a short-range ordered state by quenching from 1120 K. As expected due to the nearby located L1₂ ordered structure, diffuse maxima are seen close to the X position. Separation of the diffuse scattering into short-range order scattering and displacement scattering was performed by the method of Georgopoulos and Cohen. The short-range order parameters remain nearly unchanged for both measurements and yield effective pair interaction parameters that properly reproduce the order-disorder transition temperature. On the other side, differences are observed in the species-dependent static atomic displacements of the first two coordination shells for both measurements. This change close to the Curie temperature is compared with literature data in Ni-Fe where two measurement temperatures were chosen well below the Curie temperature.