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Atomic structure at the nanoscale a 21st century materials challenge
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Recently: nanocrystalline materials

Lanthanum Aluminate glass

J. Du and L.R. Corales, J. Non-Cryst. Solids (2007)

APPROACH

Slide 9

Pair Distribution Function from total scattering experiments

Pair Distribution Function from total scattering experiments

Raw data

Structure function

PDF

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Slide 10

How can we get short range structural information?

How can we get short range structural information?

Pair Distribution Function from total scattering experiments

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Slide 11

Pair Distribution Function: info on different lengthscales

Pair Distribution Function: info on different lengthscales

Strength of the Pair Distribution Function

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Slide 12

PDF primer: C60

PDF primer: C60

Pair Distribution Function: info on different lengthscales

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Slide 13

Pair Distribution Function: Q-space resolution effect

Pair Distribution Function: Q-space resolution effect

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Slide 14

Pair Distribution Function: rapid data collection mode

Pair Distribution Function: rapid data collection mode

Rapid Acquisition PDF (RAPDF) at a synchrotoron:

Measuring PDFs in a few seconds

P. Chupas et al, J. Appl. Cryst. 36, 1342-1347 (2003).

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Slide 15

Pair Distribution Function: rapid data collection mode

Pair Distribution Function: rapid data collection mode

P. Chupas et al, J. Appl. Cryst. 40, 463-470 (2007).

Application of a large-area, high-sensitivity, fast readout,

flat-panel GE detector based on an amorphous silicon

Nickel data, 0.03s collection time, Qmax 28 Å-1

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Slide 16

Pair Distribution Function: modeling

Pair Distribution Function: modeling

Ni

300K Ni data from GPPD at IPNS, ANL

data

difference

model

PDF Programs

PDFgetX1

PDFgetN1

PDFgui2 (PDFfit)

1 http://nirt.pa.msu.edu

2 http://www.diffpy.org/

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Slide 17

Nanometer scale structure of CuIr2S4

Nanometer scale structure of CuIr2S4

Local structural aspects of the metal-insulator transition

in CuIr2S4

- X-ray total scattering study -

Collaboration with: J.F. Mitchell, MSD, Argonne Nat. Lab.

Credits: Y.S. Hor, A.S. Masadeh, H.J. Kim, P. Juhas, S.J.L. Billinge

HIGHLIGHT

Slide 18

HIGHLIGHT

HIGHLIGHT

The role of lattice geometry – frustration

Spinel structure: AB2X4 Crystallizes in the cubic (isometric) crystal system B-sublattice – pyrochlore – corner-shared tetrahedra This sublattice promotes frustration, interesting physics arises in spin (AF interactions) and charge (half-integer valence) sectors!

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