Structure determination of Pb13Mn9O25

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The presentation shows the main points from the publication about how thee structure of Pb13Mn9O25 was solved using transmission electron microscopy.

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Structure determination of Pb13Mn9O25

  1. 1. Pb13Mn9O25, a complex oxide solved from transmission electron microscopy data
  2. 2. Ultramicroscopy 110 (2010) 881–890
  3. 3. Problem to solve New unknown compound in multiple phased sample All phases perovskite based Peaks overlap in X- ray data, so no solution from that
  4. 4. So we turn to the transmission electron microscope...
  5. 5. Electron diffraction gives us the cell parameters and space group.
  6. 6. a=b=14.2 Å=ap√13 c=3.9 Å=ap P4/m
  7. 7. EELS and EDX give us the composition.
  8. 8. Pb13Mn9O5
  9. 9. We collect the intensities of the reflections from precession electron diffraction data.
  10. 10. We feed the intensities and all collected data to direct methods (SIR2008)
  11. 11. Pb Mn Perovskite subcell Out comes a solution for the cation positions. Mn-vacancy
  12. 12. Pb Mn Perovskite subcell There are ordered manganese vacancies. Mn-vacancy
  13. 13. But where is the oxygen?
  14. 14. HAADF-STEM confirms that Mn is missing, but gives no info on oxygen
  15. 15. We find the oxygen with a global optimization in direct space (FOX) using the output from direct methods as input.
  16. 16. Structure is solved with ... two solutions !?
  17. 17. E = -7.42 eV E = -11.1 eV Structure optimisation favors one model
  18. 18. The calculated images for this model agree well with the experimental HREM images
  19. 19. Joke Hadermann, Artem M. Abakumov, Alexander A. Tsirlin, Mauro Gemmi, Hans D’Hondt, Vladimir P.Filonenko, Julie Gonnissen, Haiyan Tan, Johan Verbeeck, HelgeRosner, EvgenyV.Antipov All precise details and data can be found in the publication Ultramicroscopy 110 (2010) 881–890 by the authors Direct space structure solution from precession electron diffraction data: Resolving heavy and light scatterers in Pb13Mn9O25

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