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MI: Fachverband Mikrosonden

MI 11: Crystallography in Materials Science (KR jointly with DF, MI)

MI 11.6: Vortrag

Donnerstag, 3. April 2014, 16:45–17:00, CHE 184

White beam synchrotron x-ray topography of sapphire single crystals — •Atefeh Jafari^1,2, Angelica Cecilia³, Jürgen Härtwig⁴, Andreas Danilewsky⁵, Dimitrios Bessas⁴, Viktor Asadchikov⁶, Boris Roschin⁶, Denis Zolotov⁶, Alexander Deryabin⁶, Ilya Sergeev⁷, Svetoslav Stankov³, Tilo Baumbach³, Pavel Alexeev^1,7, Hans-Christian Wille⁷, and Raphaël Hermann^1,2 — ¹Jülich Centre for Neutron Science JCNS and Peter Grünberg Institute PGI, JARA-FIT, Forschungszentrum Jülich, Germany — ²Faculté des Sciences, Université de Liège, Liège, Belgium — ³Institute for Photon Science and Synchrotron Radiation, KIT, Germany — ⁴European Synchrotron Radiation Facility, Grenoble, France — ⁵Crystallographic institute, University of Freiburg,Germany — ⁶Shubnikov Institute of Crystallography, RAS, Moscow, Russia — ⁷Deutsches Elektronen-Synchrotron, Hamburg, Germany

Sapphire single crystals grown by different techniques have been assessed with white beam and meV-resolution synchrotron x-ray topography at ANKA, KIT and PETRA III, DESY, and ESRF, respectively. Excellent crystal quality is required for the use in backscattering x-ray monochromators for nuclear resonance scattering with resonance energies above 30 keV. X-ray topography reveals defects and dislocations and hints at their origin. Crystals grown by the Kyropoulos method show the lowest dislocation density. Support of the Helmholtz-Russia joint research group HRJRG-402, ANKA, PETRA III and ESRF is acknowledged.