Structure determination of Pb13Mn9O25

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Pb 13 Mn 9 O 25 , a complex oxide solved from transmission electron microscopy data

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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.

Transcript of Structure determination of Pb13Mn9O25

Page 1: Structure determination of Pb13Mn9O25

Pb13Mn9O25, a complex oxide

solved from transmission

electron microscopy data

Page 3: Structure determination of Pb13Mn9O25

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

Page 13: Structure determination of Pb13Mn9O25

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

Page 19: Structure determination of Pb13Mn9O25

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