Table 3 Best fit parameters obtained by fitting the experimental EXAFS of the ACuFe sample at the Fe K-edge with a 4 shell model in the case of the tetrahedral sites and a 5 shell model in the case of the octahedral sites using a model of cubic copper ferrite. Coordination numbers (N), interatomic distances (R), Debye-Waller factors, S02, ΔE0 and R-factor are shown.

From: Evidence of a cubic iron sub-lattice in t-CuFe2O4 demonstrated by X-ray Absorption Fine Structure

ACuFe

Fe K-edge

Abs-Backscatter

N

σ2(Å2)

R(Å)

Occupancy

FeA-O

4.0

0.001 ± 0.001

1.88 ± 0.01

0.50

FeA-FeB*

12.0

0.009 ± 0.003

3.45 ± 0.04

0.25

FeA-CuB*

12.0

0.009 ± 0.003

3.45 ± 0.04

0.25

FeA-O***

12.0

0.01 ± 0.06

3.6 ± 0.1

0.50

FeA- FeA

4.0

0.006 ± 0.005

3.6 ± 0.1

0.50

FeB-O

6.0

0.003 ± 0.001

2.00 ± 0.01

0.50

FeB-FeB**

6.0

0.007 ± 0.001

2.98 ± 0.01

0.25

FeB-CuB**

6.0

0.007 ± 0.001

2.98 ± 0.01

0.25

FeB-FeA*

6.0

0.009 ± 0.003

3.45 ± 0.04

0.50

FeB-O***

2.0

0.01 ± 0.6

3.6 ± 0.1

0.50

FeB-O

6.0

0.03 ± 0.3

3.65

0.50

S 0 2 = 0.7

ΔE 0  = −2.64 ± 0.73 eV

R-factor = 0.013

  1. *The distances involving the Fe3+ absorber in the tetrahedral site with the ions located in the tetrahedral sites, and the distances involving the Fe3+ absorber in the octahedral site with the Cu2+ located in the tetrahedral sites, are split in contributions with the same interatomic distances and Debye-Waller factors, as described in the text. **The distances involving the Fe3+ absorber in the octahedral site with the ions located in the octahedral sites are split into two contributions, as described in the text. ***The distances and Debye-Waller factors involving two Fe-O distances which are intrinsically different from a crystallographic point of view, but too close to be distinguished by EXAFS, were kept to the same values, as described in the text.
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