ISSN:
1432-2021
Keywords:
Key words Mössbauer spectroscopy
;
Perovskite structure
;
Ferric iron
;
Electron delocalisation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Abstract Mössbauer spectra were recorded at multiple temperatures between 80 and 293 K to study the nature of Fe3+ in Fe0.05Mg0.95SiO3 perovskite that had been synthesised in a multianvil press at 1650 °C and 25 GPa at its mimimum stability limit. The Mössbauer data were fitted to a model with quadrupole splitting distributions (Fe2+) and Lorentzian lineshapes (Fe3+ and Fen+). The centre shift data were fitted to a Debye model with the following results: ΘM (Fe2+)=365±52 K and ΘM (Fe3+)=476±96 K. Hyperfine parameter data for Fe3+ suggest occupation of the octahedral site only. The average valence seen by the Mössbauer effect in rapid electron exchange that occurs between Fe2+ and Fe3+ is calculated from the hyperfine parameters to be 2.50±0.07. Correction of area fractions for site-dependent recoil-free fractions gives a value for Fe3+/∑Fe of 9.4±1.4%, which is independent of temperature. A perovskite phase of similar composition synthesised in the multianvil press at higher oxygen fugacity gives a value for Fe3+/∑Fe of 16±3%, where Fe3+ appears to occupy both sites in the perovskite structure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002690050117
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