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Title: Electronic and magnetic structures of the postperovskite-type Fe{sub 2}O{sub 3} and implications for planetary magnetic records and deep interiors.

Abstract

Recent studies have shown that high pressure (P) induces the metallization of the Fe{sup 2+}-O bonding, the destruction of magnetic ordering in Fe, and the high-spin (HS) to low-spin (LS) transition of Fe in silicate and oxide phases at the deep planetary interiors. Hematite (Fe{sub 2}O{sub 3}) is an important magnetic carrier mineral for deciphering planetary magnetism and a proxy for Fe in the planetary interiors. Here, we present synchrotron Moessbauer spectroscopy and X-ray diffraction combined with ab initio calculations for Fe{sub 2}O{sub 3} revealing the destruction of magnetic ordering at the hematite {yields} Rh{sub 2}O{sub 3}-II type (RhII) transition at 70 GPa and 300 K, and then the revival of magnetic ordering at the RhII {yields} postperovskite (PPv) transition after laser heating at 73 GPa. At the latter transition, at least half of Fe{sup 3+} ions transform from LS to HS and Fe{sub 2}O{sub 3} changes from a semiconductor to a metal. This result demonstrates that some magnetic carrier minerals may experience a complex sequence of magnetic ordering changes during impact rather than a monotonic demagnetization. Also local Fe enrichment at Earth's core-mantle boundary will lead to changes in the electronic structure and spin state of Fe in silicatemore » PPv. If the ultra-low-velocity zones are composed of Fe-enriched silicate PPv and/or the basaltic materials are accumulated at the lowermost mantle, high electrical conductivity of these regions will play an important role for the electromagnetic coupling between the mantle and the core.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF)
OSTI Identifier:
951902
Report Number(s):
ANL/XSD/JA-64151
Journal ID: ISSN 0027-8424; PNASA6; TRN: US0902339
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Proc. Natl. Acad. Sci. USA
Additional Journal Information:
Journal Volume: 106; Journal Issue: 14 ; Apr. 7, 2009; Journal ID: ISSN 0027-8424
Country of Publication:
United States
Language:
ENGLISH
Subject:
43 PARTICLE ACCELERATORS; BONDING; DEMAGNETIZATION; ELECTRIC CONDUCTIVITY; ELECTRONIC STRUCTURE; HEATING; HEMATITE; LASERS; MAGNETISM; MOESSBAUER EFFECT; OXIDES; SILICATES; SPIN; SYNCHROTRONS; X-RAY DIFFRACTION

Citation Formats

Shim, S H, Bengtson, A, Morgan, D, Sturhahn, W, Catalli, K, Zhao, J, Lerche, M, Prakapenka, V, X-Ray Science Division, Massachusetts Inst. of Tech., Univ. of Wisconsin, Carnegie Institution of Washington, and Univ. of Chicago. Electronic and magnetic structures of the postperovskite-type Fe{sub 2}O{sub 3} and implications for planetary magnetic records and deep interiors.. United States: N. p., 2009. Web. doi:10.1073/pnas.0808549106.
Shim, S H, Bengtson, A, Morgan, D, Sturhahn, W, Catalli, K, Zhao, J, Lerche, M, Prakapenka, V, X-Ray Science Division, Massachusetts Inst. of Tech., Univ. of Wisconsin, Carnegie Institution of Washington, & Univ. of Chicago. Electronic and magnetic structures of the postperovskite-type Fe{sub 2}O{sub 3} and implications for planetary magnetic records and deep interiors.. United States. https://doi.org/10.1073/pnas.0808549106
Shim, S H, Bengtson, A, Morgan, D, Sturhahn, W, Catalli, K, Zhao, J, Lerche, M, Prakapenka, V, X-Ray Science Division, Massachusetts Inst. of Tech., Univ. of Wisconsin, Carnegie Institution of Washington, and Univ. of Chicago. Tue . "Electronic and magnetic structures of the postperovskite-type Fe{sub 2}O{sub 3} and implications for planetary magnetic records and deep interiors.". United States. https://doi.org/10.1073/pnas.0808549106.
@article{osti_951902,
title = {Electronic and magnetic structures of the postperovskite-type Fe{sub 2}O{sub 3} and implications for planetary magnetic records and deep interiors.},
author = {Shim, S H and Bengtson, A and Morgan, D and Sturhahn, W and Catalli, K and Zhao, J and Lerche, M and Prakapenka, V and X-Ray Science Division and Massachusetts Inst. of Tech. and Univ. of Wisconsin and Carnegie Institution of Washington and Univ. of Chicago},
abstractNote = {Recent studies have shown that high pressure (P) induces the metallization of the Fe{sup 2+}-O bonding, the destruction of magnetic ordering in Fe, and the high-spin (HS) to low-spin (LS) transition of Fe in silicate and oxide phases at the deep planetary interiors. Hematite (Fe{sub 2}O{sub 3}) is an important magnetic carrier mineral for deciphering planetary magnetism and a proxy for Fe in the planetary interiors. Here, we present synchrotron Moessbauer spectroscopy and X-ray diffraction combined with ab initio calculations for Fe{sub 2}O{sub 3} revealing the destruction of magnetic ordering at the hematite {yields} Rh{sub 2}O{sub 3}-II type (RhII) transition at 70 GPa and 300 K, and then the revival of magnetic ordering at the RhII {yields} postperovskite (PPv) transition after laser heating at 73 GPa. At the latter transition, at least half of Fe{sup 3+} ions transform from LS to HS and Fe{sub 2}O{sub 3} changes from a semiconductor to a metal. This result demonstrates that some magnetic carrier minerals may experience a complex sequence of magnetic ordering changes during impact rather than a monotonic demagnetization. Also local Fe enrichment at Earth's core-mantle boundary will lead to changes in the electronic structure and spin state of Fe in silicate PPv. If the ultra-low-velocity zones are composed of Fe-enriched silicate PPv and/or the basaltic materials are accumulated at the lowermost mantle, high electrical conductivity of these regions will play an important role for the electromagnetic coupling between the mantle and the core.},
doi = {10.1073/pnas.0808549106},
url = {https://www.osti.gov/biblio/951902}, journal = {Proc. Natl. Acad. Sci. USA},
issn = {0027-8424},
number = 14 ; Apr. 7, 2009,
volume = 106,
place = {United States},
year = {2009},
month = {4}
}