Spin states of ferric iron in aluminum-bearing magnesium silicate perovskite and post-perovskite
Abstract
Ferromagnesium silicate perovskite (Pv) and post-perovskite (Ppv), the dominant mineral phases of the Earth's lower mantle, also contain up to 5 mol% of Al2O3 in this solid solution. While the iron spin states in Al-free Pv and Ppv are well understood, iron spin states in Al-bearing samples still need further clarification. Here, using a series of density functional + Hubbard U (DFT+U) calculations, we study the iron spin states in these complicated systems. Two possible substitution mechanisms, (Mg,Fe)(Si,Al)O3 and (Mg,Al)(Si,Fe)O3, for both Pv and Ppv, are considered. Our results provide useful insight for the interpretation of high-pressure experiments and further elucidate properties of the deep lower mantle.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMMR43B2137H
- Keywords:
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- 3909 MINERAL PHYSICS / Elasticity and anelasticity;
- 3919 MINERAL PHYSICS / Equations of state;
- 3924 MINERAL PHYSICS / High-pressure behavior