High‐accuracy transmission and fluorescence XAFS of zinc at 10 K, 50 K, 100 K and 150 K using the hybrid technique. (18th November 2022)

• Record Type: Journal Article
• Authors: John, Marcus W.; Sier, Daniel; Ekanayake, Ruwini S. K.; Schalken, Martin J.; Tran, Chanh Q.; Johannessen, Bernt; de Jonge, Martin D.; Kappen, Peter; Chantler, Christopher T.
• Is Part Of: Journal of synchrotron radiation. Volume 30:Part 1(2023)
• Page Start: 147
• Page End: 168
• Publication Date: 2022-11-18
• Subjects: XAFS -- hybrid technique -- transmission and fluorescence -- zinc -- thermal evolution; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577522010293
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : High‐accuracy measurement of the X‐ray absorption fine structure (XAFS) of zinc metal in a temperature series from 10 K to 150 K, including 298 K, simultaneously in transmission and fluorescence using the hybrid technique is presented: the first transition metal XAFS using the hybrid technique and at low temperatures; and the first (hybrid‐like) experiment at the Australian Synchrotron. A methodology for relative measurements and a methodology for cryostat measurements, and an approach to normalization, calibration of transmission measurements for scattering and other systematics to reference room‐temperature data and yield a defined uncertainty are presented. Abstract : The most accurate measurements of the mass attenuation coefficient for metals at low temperature for the zinc K ‐edge from 9.5 keV to 11.5 keV at temperatures of 10 K, 50 K, 100 K and 150 K using the hybrid technique are reported. This is the first time transition metal X‐ray absorption fine structure (XAFS) has been studied using the hybrid technique and at low temperatures. This is also the first hybrid‐like experiment at the Australian Synchrotron. The measured transmission and fluorescence XAFS spectra are compared and benchmarked against each other with detailed systematic analyses. A recent method for modelling self‐absorption in fluorescence has been adapted and applied to a solid sample. The XAFS spectra are analysed using eFEFFIT to provide a robust measurement of the evolution of nanostructure, including such properties as net thermal expansion and mean‐square relative displacement. This work investigates crystal dynamics, nanostructural evolution and the results of using the Debye and Einstein models to determine atomic positions. Accuracies achieved, when compared with the literature, exceed those achieved by both relative and differential XAFS, and represent a state‐of‐the‐art for future structural investigations. Bond length uncertainties are of the order of 20–40 fm.