An investigation of the electronic structure of Cu{sub 2}FeSn{sub 3-x}Ti{sub x}S{sub 8} (0{<=}x{<=}3) thiospinel spin-crossover materials by X-ray absorption spectroscopy and electronic structure calculations
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, Canada S7N 5C9 (Canada)
The spin-crossover (SCO) transition is an interesting phenomenon in which a metal center transitions from a low-spin state to a high-spin state (or vice versa) upon some external perturbation. Only a few studies have investigated the SCO transition in crystalline compounds and the Cu{sub 2}FeSn{sub 3-x}Ti{sub x}S{sub 8} thiospinels present an opportunity for such a study. Fe K-XANES has been used to investigate the changes in the electronic structure of these materials as Ti is substituted for Sn. The room-temperature Fe K-edge XANES spectra showed that the pre-edge intensity increased with increasing Ti content as a result of the Fe-S bond becoming more covalent. Ti K- and S K-edge XANES spectra confirmed this analysis. Electronic structure calculations were also performed to aid in the interpretation of the XANES spectra. Temperature-dependent Fe K-edge XANES spectra were further collected to study the SCO transition and showed that the main-edge features decreased in intensity with decreasing temperature, corresponding to variations in the average Fe{sup 2+} spin-state. - Graphical abstract: The Cu{sub 2}FeSn{sub 3-x}Ti{sub x}S{sub 8} spin-crossover materials have been investigated by XANES. The pre-edge region of the Fe K-edge spectra increases with greater Ti incorporation because of the Fe-S bonds becoming more covalent. Highlights: Black-Right-Pointing-Pointer Cu{sub 2}FeSn{sub 3-x}Ti{sub x}S{sub 8} thiospinels were investigated by XANES. Black-Right-Pointing-Pointer The covalency of the Fe-S and Ti-S bonds increases with greater Ti incorporation. Black-Right-Pointing-Pointer T-dependent Fe K-edge XANES spectra were collected to investigate SCO transitions. Black-Right-Pointing-Pointer Covalent bonding makes study of the SCO transition difficult by Fe K-edge XANES. Black-Right-Pointing-Pointer The bonding interactions were investigated through examination of S K-edge spectra.
- OSTI ID:
- 22131222
- Journal Information:
- Journal of Solid State Chemistry, Vol. 197; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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