Separated Anomalous Scattering Amplitudes for the Inequivalent Cu Sites in YBa2Cu3O7-δusing DAFS
| Autor: | Matthew Newville, Julie O. Cross, Charles E. Bouldin, J. C. Woicik, Larry B. Sorensen, Hans Stragier |
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| Rok vydání: | 1997 |
| Předmět: |
010302 applied physics
Diffraction Anomalous scattering Condensed matter physics Chemistry General Physics and Astronomy Inverse 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics Scattering amplitude Matrix (mathematics) Amplitude [PHYS.HIST]Physics [physics]/Physics archives 0103 physical sciences 0210 nano-technology Structure factor Linear combination |
| Zdroj: | Journal de Physique IV Proceedings Journal de Physique IV Proceedings, EDP Sciences, 1997, 7 (C2), pp.C2-745-C2-747. ⟨10.1051/jp4:1997224⟩ |
| ISSN: | 1155-4339 1764-7177 |
| DOI: | 10.1051/jp4:1997224 |
| Popis: | The separate complex resonant scattering amplitudes for the two inequivalent Cu sites in YBa 2 CU 3 O 7-δ have been determined using diffraction anomalous fine structure (DAFS). The combined amplitudes Δf(Q,E) for eight specular (00l) reflections were isolated from the measured intensity using the iterative dispersion algorithm of Pickering, et al., modified to accommodate contributions to the imaginary part of the scattering amplitude from the heavy Ba and Y atoms. The individual site response functions f(E) were solved by singular value decomposition of the matrix of crystallographic coefficients and applying the inverse matrix to Af(Q> E) at each value of energy. For comparison, a second set of coefficients was obtained by simultaneously fitting the DAFS fine structure functions X(Q>k) using the computer program FEFFIT under a set of constraints. The X(Q, k) were modeled as linear combinations of the two Cu site X(κ) functions using a kinematic structure factor model with Q as the independent variable and theoretical X(κ) from FEFF7. |
| Databáze: | OpenAIRE |
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