气候变化领域集成服务门户(CCPortal): Spin Transitions and Compressibility of ε-Fe7N3 and γ′-Fe4N: Implications for Iron Alloys in Terrestrial Planet Cores

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DOI	10.1029/2020JB020660
	Spin Transitions and Compressibility of ε-Fe7N3 and γ′-Fe4N: Implications for Iron Alloys in Terrestrial Planet Cores
	Lv M.; Liu J.; Zhu F.; Li J.; Zhang D.; Xiao Y.; Dorfman S.M.
发表日期	2020
ISSN	21699313
卷号	125 期号:11
英文摘要	Iron nitrides are possible constituents of the cores of Earth and other terrestrial planets. Pressure-induced magnetic changes in iron nitrides and effects on compressibility remain poorly understood. Here we report synchrotron X-ray emission spectroscopy (XES) and X-ray diffraction (XRD) results for ε-Fe7N3 and γ′-Fe4N up to 60 GPa at 300 K. The XES spectra reveal completion of high- to low-spin transition in ε-Fe7N3 and γ′-Fe4N at 43 and 34 GPa, respectively. The completion of the spin transition induces stiffening in bulk modulus of ε-Fe7N3 by 22% at ~40 GPa, but has no resolvable effect on the compression behavior of γ′-Fe4N. Fitting pressure-volume data to the Birch-Murnaghan equation of state yields V0 = 83.29 ± 0.03 (Å3), K0 = 232 ± 9 GPa, K0′ = 4.1 ± 0.5 for nonmagnetic ε-Fe7N3 above the spin transition completion pressure, and V0 = 54.82 ± 0.02 (Å3), K0 = 152 ± 2 GPa, K0′ = 4.0 ± 0.1 for γ′-Fe4N over the studied pressure range. By reexamining evidence for spin transition and effects on compressibility of other candidate components of terrestrial planet cores, Fe3S, Fe3P, Fe7C3, and Fe3C based on previous XES and XRD measurements, we located the completion of high- to low-spin transition at ~67, 38, 50, and 30 GPa at 300 K, respectively. The completion of spin transitions of Fe3S, Fe3P, and Fe3C induces elastic stiffening, whereas that of Fe7C3 induces elastic softening. Changes in compressibility at completion of spin transitions in iron-light element alloys may influence the properties of Earth's and planetary cores. ©2020. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187513
作者单位	Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, United States; Now at Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing, China; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, United States; Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, United States; GeoSoiEnviroCARS, University of Chicago, Chicago, IL, United States; High Pressure Collaborative Access Team (HPCAT), X-ray Science Division, Argonne National Laboratory, Argonne, IL, United States
推荐引用方式 GB/T 7714	Lv M.,Liu J.,Zhu F.,等. Spin Transitions and Compressibility of ε-Fe7N3 and γ′-Fe4N: Implications for Iron Alloys in Terrestrial Planet Cores[J],2020,125(11).
APA	Lv M..,Liu J..,Zhu F..,Li J..,Zhang D..,...&Dorfman S.M..(2020).Spin Transitions and Compressibility of ε-Fe7N3 and γ′-Fe4N: Implications for Iron Alloys in Terrestrial Planet Cores.Journal of Geophysical Research: Solid Earth,125(11).
MLA	Lv M.,et al."Spin Transitions and Compressibility of ε-Fe7N3 and γ′-Fe4N: Implications for Iron Alloys in Terrestrial Planet Cores".Journal of Geophysical Research: Solid Earth 125.11(2020).