Electronic spin state of ferric iron in Al-bearing perovskite in the lower mantle

Abstract

[1] We investigate the effect of pressure on the electronic spin state of ferric iron on Al-bearing MgSiO3-perovskite using first-principle computations. Ferric iron (6.25 mol%) and Al (6.25 mol%) substitute for Mg and Si respectively. Five substitution models on different atomic position pairs are examined. Our results show that spin state transition from high spin (HS) to low spin (LS) occurs on the Fe ions at high pressure, while there is no stability field for the intermediate spin state. Fe alone can be responsible for the spin state transition. The five models witness a transition pressure ranging from 97–126 GPa. Differential stress can change the pressure for the spin collapse. The lowest pressure spin state transition occurs where Al and Fe are in adjacent sites. These results are one explanation to the reported experimental observations that the spin transition occurs over a wide pressure range. This finding may have important implications for the dynamics and seismic signature of the lower mantle. Citation: Li, L., J. P. Brodholt, S. Stackhouse, D. J. Weidner, M. Alfredsson, and G. D. Price (2005), Electronic spin state of ferric iron in Albearing perovskite in the lower mantle, Geophys. Res. Lett., 32, L17307, doi:10.1029/2005GL023045.

3 Figures and Tables

Cite this paper

@inproceedings{Li2005ElectronicSS, title={Electronic spin state of ferric iron in Al-bearing perovskite in the lower mantle}, author={Li Li and John P. Brodholt and Stephen Stackhouse and Donald J. Weidner and M. Alfredsson and David William Price}, year={2005} }