| Autor: |
Potapkin V; European Synchrotron Radiation Facility, BP 220, Grenoble F-38043, France., McCammon C, Glazyrin K, Kantor A, Kupenko I, Prescher C, Sinmyo R, Smirnov GV, Chumakov AI, Rüffer R, Dubrovinsky L |
| Jazyk: |
angličtina |
| Zdroj: |
Nature communications [Nat Commun] 2013; Vol. 4, pp. 1427. |
| DOI: |
10.1038/ncomms2436 |
| Abstrakt: |
Iron can adopt different spin states in the lower mantle. Previous studies indicate that the dominant lower-mantle phase, magnesium silicate perovskite (which contains at least half of its iron as Fe(3+)), undergoes a Fe(3+) high-spin to low-spin transition that has been suggested to cause seismic velocity anomalies and a drop in laboratory-measured electrical conductivity. Here we apply a new synchrotron-based method of Mössbauer spectroscopy and show that Fe(3+) remains in the high-spin state in lower-mantle perovskite at conditions throughout the lower mantle. Electrical conductivity measurements show no conductivity drop in samples with high Fe(3+), suggesting that the conductivity drop observed previously on samples with high Fe(2+) is due to a transition of Fe(2+) to the intermediate-spin state. Correlation of transport and elastic properties of lower-mantle perovskite with electromagnetic and seismic data may provide a new probe of heterogeneity in the lower mantle. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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