title: The effect of iron spin transition on electrical conductivity of (Mg,Fe)O magnesiowüstite.
abstract: We measured the electrical conductivity of Mg0.81Fe0.19O magnesiowüstite, one of the important minerals comprising Earth's lower mantle, at high pressures up to 135 GPa and 300 K in a diamond-anvil cell (DAC). The results demonstrate that the electrical conductivity increases with increasing pressure to about 60 GPa and exhibits anomalous behavior at higher pressures; it conversely decreases to around 80 GPa and again increases very mildly with pressure. These observed changes may be explained by the high-spin to low-spin transition of iron in magnesiowüstite that was previously reported to occur in a similar pressure range. A very small pressure effect on the electrical conductivity above 80 GPa suggests that a dominant conduction mechanism changes by this electronic spin transition. The electrical conductivity below 2000-km depth in the mantle may be much smaller than previously thought, since the spin transition takes place also in (Mg,Fe)SiO3 perovskite.
authors.affiliation: Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan .
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohta
authors.forename: Kei
authors.initials: K
authors.lastname: Hirose
authors.forename: Suzue
authors.initials: S
authors.lastname: Onoda
authors.forename: Katsuya
authors.initials: K
authors.lastname: Shimizu
keywords: electrical conductivity; high-pressure; magnesiowüstite; spin transition
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