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![[Figure 4]](ok5025fig4mag.jpg)
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Figure 4
(a) Magnitude of the Fourier transform |FT[χ(k)k3]| of the k3-weighted EXAFS fine structures χ(k)k3 measured for an Nb metal foil (8 µm thickness) at room temperature prior to any heat treatment (blue line) and after a heat-treatment in the new high temperature cell under vacuum conditions close to 10−6 mbar for 1 h (dark blue line), 2 h (green line) and 4 h (red line), respectively (k-range for the FT: 2.2 Å−1 < k < 14.5 Å−1, the shown data are not corrected for phase shifts). Only very small changes are detectable after 4 h of the heat treatment. In the inset, the related near-edge X-ray absorption spectra are compared with negligible changes after the heat treatments. (b) Exemplary fit of the EXAFS data with a two-shell model using the first and second Nb–Nb coordinations of the base-centred-cubic lattice for the sample treated for 2 h under vacuum; the experimental data (green line) as well as the fit (yellow line) are shown. In the inset, the back-transformed k3-weighted EXAFS fine structures χ(k)k3 (data from 1.5 Å to 3.4 Å in the FT as indicated by vertical dotted blue lines) are shown for the experimental data (green squares) and the fit (yellow line). See text for more details. |
![[Figure 4]](ok5025fig4.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
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