Pressure-induced magnetic transition and sound velocities of Fe3C: Implications for carbon in the Earth's inner core

Lili Gao, Bin Chen, Jingyun Wang, Esen E. Alp, Jiyong Zhao, Michael Lerche, Wolfgang Sturhahn, Henry P. Scott, Fang Huang, Yang Ding, Stanislav V. Sinogeikin, Craig C. Lundstrom, Jay D. Bass, Jie Li

Research output: Contribution to journalArticlepeer-review

Abstract

We have carried out nuclear resonant scattering measurements on 57Fe-enriched Fe3C between 1 bar and 50 GPa at 300 K. Synchrotron Mössbauer spectra reveal a pressure-induced magnetic transition in Fe3C between 4.3 and 6.5 GPa. On the basis of our nuclear resonant inelastic X-ray scattering spectra and existing equation-of-state data, we have derived the compressional wave velocity VP and shear wave velocity VS for the high-pressure nonmagnetic phase, which can be expressed as functions of density (ρ): VP(km/s) = -3.99 + 1.29ρ(g/ cm3) and VS(km/s) = 1.45 + 0.24ρ(g/cm3). The addition of carbon to iron-nickel alloy brings density, VP and VS closer to seismic observations, supporting carbon as a principal light element in the Earth's inner core.

Original languageEnglish (US)
Article numberL17306
JournalGeophysical Research Letters
Volume35
Issue number17
DOIs
StatePublished - Sep 16 2008

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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