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Electronic spin state of ferric iron in Al‐bearing perovskite in the lower mantle
Author(s) -
Li Li,
Brodholt John P.,
Stackhouse Stephen,
Weidner Donald J.,
Alfredsson Maria,
Price G. David
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023045
Subject(s) - spin states , spin transition , perovskite (structure) , ferric , spin (aerodynamics) , ferric iron , mantle (geology) , materials science , ion , condensed matter physics , chemistry , geology , crystallography , thermodynamics , physics , metallurgy , geophysics , organic chemistry , ferrous
We investigate the effect of pressure on the electronic spin state of ferric iron on Al‐bearing MgSiO 3 ‐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 3+ ions at high pressure, while there is no stability field for the intermediate spin state. Fe 3+ 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 3+ and Fe 3+ 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.