High-spin Fe2+ and Fe3+ in single-crystal aluminous bridgmanite in the lower mantle

Jung Fu Lin; Zhu Mao; Jing Yang; Jin Liu; Yuming Xiao; Paul Chow; Takuo Okuchi

doi:10.1002/2016GL069836

High-spin Fe²⁺ and Fe³⁺ in single-crystal aluminous bridgmanite in the lower mantle

Jung Fu Lin, Zhu Mao, Jing Yang, Jin Liu, Yuming Xiao, Paul Chow, Takuo Okuchi

Institute for Planetary Materials

Research output: Contribution to journal › Article › peer-review

19 Citations (Scopus)

Abstract

Spin and valence states of iron in single-crystal bridgmanite (Mg_0.89Fe_0.12Al_0.11Si_0.89O₃) are investigated using X-ray emission and Mössbauer spectroscopies with laser annealing up to 115 GPa. The results show that Fe predominantly substitutes for Mg²⁺ in the pseudo-dodecahedral A site, in which 80% of the iron is Fe³⁺ that enters the lattice via the charge-coupled substitution with Al³⁺ in the octahedral B site. The total spin momentum and hyperfine parameters indicate that these ions remain in the high-spin state with Fe²⁺ having extremely high quadrupole splitting due to lattice distortion. (Al,Fe)-bearing bridgmanite is expected to contain mostly high-spin, A-site Fe³⁺, together with a smaller amount of A-site Fe²⁺, that remains stable throughout the region. Even though the spin transition of B-site Fe³⁺ in bridgmanite was reported to cause changes in its elasticity at high pressures, (Fe,Al)-bearing bridgmanite with predominantly A-site Fe will not exhibit elastic anomalies associated with the spin transition.

Original language	English
Pages (from-to)	6952-6959
Number of pages	8
Journal	Geophysical Research Letters
Volume	43
Issue number	13
DOIs	https://doi.org/10.1002/2016GL069836
Publication status	Published - Jul 16 2016

Keywords

bridgmanite
high pressure
lower mantle
mineral physics
spin and valence states
spin transition

ASJC Scopus subject areas

Geophysics
Earth and Planetary Sciences(all)

Access to Document

10.1002/2016GL069836

Cite this

@article{cde064efdd2743d4a0467179b60cd37b,

title = "High-spin Fe2+ and Fe3+ in single-crystal aluminous bridgmanite in the lower mantle",

abstract = "Spin and valence states of iron in single-crystal bridgmanite (Mg0.89Fe0.12Al0.11Si0.89O3) are investigated using X-ray emission and M{\"o}ssbauer spectroscopies with laser annealing up to 115 GPa. The results show that Fe predominantly substitutes for Mg2+ in the pseudo-dodecahedral A site, in which 80% of the iron is Fe3+ that enters the lattice via the charge-coupled substitution with Al3+ in the octahedral B site. The total spin momentum and hyperfine parameters indicate that these ions remain in the high-spin state with Fe2+ having extremely high quadrupole splitting due to lattice distortion. (Al,Fe)-bearing bridgmanite is expected to contain mostly high-spin, A-site Fe3+, together with a smaller amount of A-site Fe2+, that remains stable throughout the region. Even though the spin transition of B-site Fe3+ in bridgmanite was reported to cause changes in its elasticity at high pressures, (Fe,Al)-bearing bridgmanite with predominantly A-site Fe will not exhibit elastic anomalies associated with the spin transition.",

keywords = "bridgmanite, high pressure, lower mantle, mineral physics, spin and valence states, spin transition",

author = "Lin, {Jung Fu} and Zhu Mao and Jing Yang and Jin Liu and Yuming Xiao and Paul Chow and Takuo Okuchi",

note = "Funding Information: We acknowledge N. Purevjav, N. Tomiaka, V. Prapapenka, Y. Hong, J. Zhao, and B. Li for their assistance. We also thank H. Hsu and S. Jacobsen for their constructive comments. J.F. Lin acknowledges supports from the Geophysics and CSEDI Programs of the NSF and the Visiting Professorship Program of the Okayama University. We also thank C. McCammon for analyzing the M?ssbauer spectrum of the crystals at ambient conditions. Portions of this work were performed at HPCAT, GSECARS, and XOR3 sectors of the APS. HPCAT is supported by CIW, CDAC, UNLV, and LLNL through funding from DOE-NNSA, DOE-BES, and NSF. APS is supported by 263 DOE-BES, under contract DE-AC02-06CH11357. Part of this work by T.O. was supported by JSPS KAKENHI (26287135). Experimental data have been shown in Figures, S1, and S2. Publisher Copyright: {\textcopyright}2016. American Geophysical Union. All Rights Reserved.",

year = "2016",

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doi = "10.1002/2016GL069836",

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AU - Lin, Jung Fu

AU - Mao, Zhu

AU - Yang, Jing

AU - Liu, Jin

AU - Xiao, Yuming

AU - Chow, Paul

AU - Okuchi, Takuo

N1 - Funding Information: We acknowledge N. Purevjav, N. Tomiaka, V. Prapapenka, Y. Hong, J. Zhao, and B. Li for their assistance. We also thank H. Hsu and S. Jacobsen for their constructive comments. J.F. Lin acknowledges supports from the Geophysics and CSEDI Programs of the NSF and the Visiting Professorship Program of the Okayama University. We also thank C. McCammon for analyzing the M?ssbauer spectrum of the crystals at ambient conditions. Portions of this work were performed at HPCAT, GSECARS, and XOR3 sectors of the APS. HPCAT is supported by CIW, CDAC, UNLV, and LLNL through funding from DOE-NNSA, DOE-BES, and NSF. APS is supported by 263 DOE-BES, under contract DE-AC02-06CH11357. Part of this work by T.O. was supported by JSPS KAKENHI (26287135). Experimental data have been shown in Figures, S1, and S2. Publisher Copyright: ©2016. American Geophysical Union. All Rights Reserved.

PY - 2016/7/16

Y1 - 2016/7/16

N2 - Spin and valence states of iron in single-crystal bridgmanite (Mg0.89Fe0.12Al0.11Si0.89O3) are investigated using X-ray emission and Mössbauer spectroscopies with laser annealing up to 115 GPa. The results show that Fe predominantly substitutes for Mg2+ in the pseudo-dodecahedral A site, in which 80% of the iron is Fe3+ that enters the lattice via the charge-coupled substitution with Al3+ in the octahedral B site. The total spin momentum and hyperfine parameters indicate that these ions remain in the high-spin state with Fe2+ having extremely high quadrupole splitting due to lattice distortion. (Al,Fe)-bearing bridgmanite is expected to contain mostly high-spin, A-site Fe3+, together with a smaller amount of A-site Fe2+, that remains stable throughout the region. Even though the spin transition of B-site Fe3+ in bridgmanite was reported to cause changes in its elasticity at high pressures, (Fe,Al)-bearing bridgmanite with predominantly A-site Fe will not exhibit elastic anomalies associated with the spin transition.

AB - Spin and valence states of iron in single-crystal bridgmanite (Mg0.89Fe0.12Al0.11Si0.89O3) are investigated using X-ray emission and Mössbauer spectroscopies with laser annealing up to 115 GPa. The results show that Fe predominantly substitutes for Mg2+ in the pseudo-dodecahedral A site, in which 80% of the iron is Fe3+ that enters the lattice via the charge-coupled substitution with Al3+ in the octahedral B site. The total spin momentum and hyperfine parameters indicate that these ions remain in the high-spin state with Fe2+ having extremely high quadrupole splitting due to lattice distortion. (Al,Fe)-bearing bridgmanite is expected to contain mostly high-spin, A-site Fe3+, together with a smaller amount of A-site Fe2+, that remains stable throughout the region. Even though the spin transition of B-site Fe3+ in bridgmanite was reported to cause changes in its elasticity at high pressures, (Fe,Al)-bearing bridgmanite with predominantly A-site Fe will not exhibit elastic anomalies associated with the spin transition.

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KW - spin and valence states

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