structure determination of pb13mn9o25
DESCRIPTION
The presentation shows the main points from the publication about how thee structure of Pb13Mn9O25 was solved using transmission electron microscopy.TRANSCRIPT
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Pb13Mn9O25, a complex oxide
solved from transmission
electron microscopy data
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Ultramicroscopy 110
(2010) 881–890
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Problem to solveNew unknown
compound in multiple
phased sampleAll phases
perovskite based
Peaks overlap in X-
ray data, so no
solution from that
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So we turn to the
transmission electron
microscope...
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Electron diffraction
gives us the cell
parameters and
space group.
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a=b=14.2 Å=ap√13c=3.9 Å=ap
P4/m
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EELS and EDX
give us the
composition.
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Pb13Mn9O5
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We collect the
intensities of the
reflections from
precession
electron
diffraction data.
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We feed the
intensities and all
collected data to
direct methods
(SIR2008)
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Pb
Mn
Perovskite subcell
Out comes a
solution for the
cation
positions.
Mn-vacancy
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Pb
Mn
Perovskite subcell
There are
ordered
manganese
vacancies.
Mn-vacancy
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But where is
the oxygen?
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HAADF-STEM
confirms that Mn is
missing, but gives
no info on oxygen
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We find the oxygen with
a global optimization in
direct space (FOX) using
the output from direct
methods as input.
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Structure is solved with ...
two solutions !?
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E = -7.42 eV E = -11.1 eV
Structure optimisation
favors one model
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The calculated images
for this model agree well
with the experimental
HREM images
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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