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Spin transition and equations of state of (Mg, Fe)O solid solutions
Author(s) -
Fei Yingwei,
Zhang Li,
Corgne Alexandre,
Watson Heather,
Ricolleau Angele,
Meng Yue,
Prakapenka Vitali
Publication year - 2007
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 - 10.1029/2007gl030712
Subject(s) - ionic radius , bulk modulus , equation of state , spin transition , materials science , analytical chemistry (journal) , spin states , diffraction , synchrotron , thermodynamics , crystallography , mineralogy , chemistry , ion , physics , inorganic chemistry , composite material , organic chemistry , chromatography , nuclear physics , optics
We have performed a series of experiments to investigate the compositional effect on the compression behavior of (Mg, Fe)O solid solutions at high pressure. The in‐situ synchrotron X‐ray diffraction data revealed abnormal volume contractions at about 40, 60, and 80 GPa for (Mg 0.80 , Fe 0.20 )O, (Mg 0.61 , Fe 0.39 )O, and (Mg 0.42 , Fe 0.58 )O, respectively. The volume contractions are associated with the reported electronic transition of high‐spin to low‐spin in Fe 2+ , and caused by the reduction of Fe 2+ ionic radius across the transition. A least‐squares fit of the compression data to the Birch‐Murnaghan equation of state yielded bulk modulus K 0 (GPa) = 160 − 10 X FeO for the high‐spin (Mg,Fe)O and K 0 = 170(3) GPa for the low‐spin (Mg,Fe)O. The equations of state of (Mg,Fe)O established in this study are directly applicable to the Earth's lower mantle in composition and pressure ranges and provide essential data for modeling the density profile of the lower mantle.