Abstract
The pressure-induced electronic spin transition of iron in ferropericlase was investigated as a function of iron content in ferropericlase by in situ electrical conductivity measurement. The electrical conductivity of ferropericlase, (Mg1-x,Fex)O (x = 0.07, 0.10, 0.13, 0.17, 0.24), was measured up to 53 GPa and 600 K using the Kawai-type multianvil apparatus equipped with sintered diamond anvils. At pressures up to 25 GPa, the electrical conductivity of ferropericlase generally increases with increasing pressure, and both the activation energy and activation volume of ferropericlase decrease with increasing iron content. For the samples with x = 0.07 and 0.10, the electrical conductivity shows a slight initial decrease and becomes constant between 25 and 40 GPa, upon which it increases slightly as the pressure increases. For the samples with higher iron content, the electrical conductivity constantly increases with pressure over the investigated pressure range. If these changes in the electrical conductivity are due to the isosymmetric high- to low-spin transition of iron in ferropericlase, this conductivity change suggests that the spin transition pressure significantly decreases with decreasing iron content in ferropericlase. Because the amount of iron in ferropericlase that coexists with the Al-bearing perovskite seems to be less than that in the Al-free perovskite, the influence of the iron partitioning between perovskite and ferropericlase by the spin transition appears in a pressure range of about 30-40 GPa in the lower mantle of the Earth.
| Original language | English |
|---|---|
| Article number | B04202 |
| Journal | Journal of Geophysical Research B: Solid Earth |
| Volume | 116 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Apr 1 2011 |
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ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
Cite this
Effect of iron content on electrical conductivity of ferropericlase with implications for the spin transition pressure. / Yoshino, Takashi; Ito, Eiji; Katsura, Tomoo; Yamazaki, Daisuke; Shan, Shuanming; Guo, Xinzhuan; Nishi, Masayuki; Higo, Yuji; Funakoshi, Ken Ichi.
In: Journal of Geophysical Research B: Solid Earth, Vol. 116, No. 4, B04202, 01.04.2011.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of iron content on electrical conductivity of ferropericlase with implications for the spin transition pressure
AU - Yoshino, Takashi
AU - Ito, Eiji
AU - Katsura, Tomoo
AU - Yamazaki, Daisuke
AU - Shan, Shuanming
AU - Guo, Xinzhuan
AU - Nishi, Masayuki
AU - Higo, Yuji
AU - Funakoshi, Ken Ichi
PY - 2011/4/1
Y1 - 2011/4/1
N2 - The pressure-induced electronic spin transition of iron in ferropericlase was investigated as a function of iron content in ferropericlase by in situ electrical conductivity measurement. The electrical conductivity of ferropericlase, (Mg1-x,Fex)O (x = 0.07, 0.10, 0.13, 0.17, 0.24), was measured up to 53 GPa and 600 K using the Kawai-type multianvil apparatus equipped with sintered diamond anvils. At pressures up to 25 GPa, the electrical conductivity of ferropericlase generally increases with increasing pressure, and both the activation energy and activation volume of ferropericlase decrease with increasing iron content. For the samples with x = 0.07 and 0.10, the electrical conductivity shows a slight initial decrease and becomes constant between 25 and 40 GPa, upon which it increases slightly as the pressure increases. For the samples with higher iron content, the electrical conductivity constantly increases with pressure over the investigated pressure range. If these changes in the electrical conductivity are due to the isosymmetric high- to low-spin transition of iron in ferropericlase, this conductivity change suggests that the spin transition pressure significantly decreases with decreasing iron content in ferropericlase. Because the amount of iron in ferropericlase that coexists with the Al-bearing perovskite seems to be less than that in the Al-free perovskite, the influence of the iron partitioning between perovskite and ferropericlase by the spin transition appears in a pressure range of about 30-40 GPa in the lower mantle of the Earth.
AB - The pressure-induced electronic spin transition of iron in ferropericlase was investigated as a function of iron content in ferropericlase by in situ electrical conductivity measurement. The electrical conductivity of ferropericlase, (Mg1-x,Fex)O (x = 0.07, 0.10, 0.13, 0.17, 0.24), was measured up to 53 GPa and 600 K using the Kawai-type multianvil apparatus equipped with sintered diamond anvils. At pressures up to 25 GPa, the electrical conductivity of ferropericlase generally increases with increasing pressure, and both the activation energy and activation volume of ferropericlase decrease with increasing iron content. For the samples with x = 0.07 and 0.10, the electrical conductivity shows a slight initial decrease and becomes constant between 25 and 40 GPa, upon which it increases slightly as the pressure increases. For the samples with higher iron content, the electrical conductivity constantly increases with pressure over the investigated pressure range. If these changes in the electrical conductivity are due to the isosymmetric high- to low-spin transition of iron in ferropericlase, this conductivity change suggests that the spin transition pressure significantly decreases with decreasing iron content in ferropericlase. Because the amount of iron in ferropericlase that coexists with the Al-bearing perovskite seems to be less than that in the Al-free perovskite, the influence of the iron partitioning between perovskite and ferropericlase by the spin transition appears in a pressure range of about 30-40 GPa in the lower mantle of the Earth.
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U2 - 10.1029/2010JB007801
DO - 10.1029/2010JB007801
M3 - Article
AN - SCOPUS:79953708231
VL - 116
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
SN - 0148-0227
IS - 4
M1 - B04202
ER -