Regensburg 2010 – scientific programme

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KR: Fachverband Kristallographie

KR 2: Crystallography in nanoscience

KR 2.8: Talk

Tuesday, March 23, 2010, 12:00–12:15, H9

Polarization dependent Diffraction Anomalous Fine Structure of rutile TiO₂ 001 and 111 reflections
— •Matthias Zschornak^1,2, Carsten Richter¹, Hartmut Stöcker¹, Tilmann Leisegang¹, Sibylle Gemming², and Dirk C. Meyer^1,3 — ¹Nachwuchsgruppe Nanostrukturphysik, Institute of Structural Physics, TU Dresden, Germany — ²Institute of Ion Beam Physics and Materials Research, FZ Dresden-Rossendorf, Germany — ³Institute of Experimental Physics, TU Bergakademie Freiberg, Germany

Energy and polarization dependent Diffraction Anomalous Fine Structure (DAFS) also known as Anisotropic Anomalous Scattering (AAS) can be employed in addition to X-ray Absorption Fine Structure (XAFS) to study electronic transitions from core states to unoccupied states. Here, we present results from resonant X-ray diffraction experiments on TiO₂ rutile, space group (136) P4₂/mnm. For this model structure, site symmetry information was extracted from determination of the structure factor tensor by refining elements of Ti atomic scattering factor tensors. Influences of oxygen vacancies on the anomalous scattering contributions have been studied on a series of rutile wafers of different oxygen concentration. Samples investigated were 10 × 10 × 1 mm³ single crystal wafers and experiments were carried out at DESY/HASYLAB beamlines C and E2 using a Si (111) double crystal monochromator in the vicinity of the Ti-K absorption edge. Considered reflections include the ‘forbidden’ 001 and allowed 111 reflection.