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The spin state of iron in minerals of Earth's lower mantle
Author(s) -
Sturhahn Wolfgang,
Jackson Jennifer M.,
Lin JungFu
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 - 10.1029/2005gl022802
Subject(s) - silicate perovskite , mantle (geology) , spin transition , geothermal gradient , spin crossover , silicate , pairing , transition zone , post perovskite , geology , spin states , condensed matter physics , geophysics , physics , superconductivity , astronomy
The spin state of Fe(II) and Fe(III) at temperatures and pressures typical for the Earth's lower mantle is discussed. We predict an extended high‐spin to low‐spin crossover region along the geotherm for Fe‐dilute systems depending on crystal‐field splitting, pairing energy, and cooperative interactions. In particular, spin transitions in ferromagnesium silicate perovskite and ferropericlase, the dominant lower mantle components, should occur in a wide temperature‐pressure range. We also derive a gradual volume change associated with such transitions in the lower mantle. The gradual density changes and the wide spin crossover regions seem incompatible with lower mantle stratification resulting from a spin transition.