Melting of compressed iron by monitoring atomic dynamics

Jennifer M. Jackson, Wolfgang Sturhahn, Michael Lerche, Jiyong Zhao, Thomas S. Toellner, E. Ercan Alp, Stanislav V. Sinogeikin, Jay D. Bass, Caitlin A. Murphy, June K. Wicks

Research output: Contribution to journalArticle

Abstract

We present a novel method for detecting the solid-liquid phase boundary of compressed iron at high temperatures using synchrotron Mössbauer spectroscopy (SMS). Our approach is unique because the dynamics of the iron atoms are monitored. This process is described by the Lamb-Mössbauer factor, which is related to the mean-square displacement of the iron atoms. Focused synchrotron radiation with 1meV bandwidth passes through a laser-heated 57Fe sample inside a diamond-anvil cell, and the characteristic SMS time signature vanishes when melting occurs. At our highest compression measurement and considering thermal pressure, we find the melting point of iron to be TM=3025±115K at P=82±5GPa. When compared with previously reported melting points for iron using static compression methods with different criteria for melting, our melting trend defines a steeper positive slope as a function of pressure. The obtained melting temperatures represent a significant step toward a reliable melting curve of iron at Earth's core conditions. For other terrestrial planets possessing cores with liquid portions rich in metallic iron, such as Mercury and Mars, the higher melting temperatures for compressed iron may imply warmer internal temperatures.

Original languageEnglish (US)
Pages (from-to)143-150
Number of pages8
JournalEarth and Planetary Science Letters
Volume362
DOIs
StatePublished - Jan 5 2013

Fingerprint

Melting
Iron
melting
iron
Monitoring
monitoring
Melting point
Synchrotrons
melting points
synchrotrons
spectroscopy
compression
Spectroscopy
Earth core
Atoms
diamond anvil cell
Diamond
liquid
terrestrial planets
temperature

Keywords

  • Dynamics
  • High-pressure
  • Iron
  • Melting
  • Mössbauer

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Jackson, J. M., Sturhahn, W., Lerche, M., Zhao, J., Toellner, T. S., Alp, E. E., ... Wicks, J. K. (2013). Melting of compressed iron by monitoring atomic dynamics. Earth and Planetary Science Letters, 362, 143-150. https://doi.org/10.1016/j.epsl.2012.11.048

Melting of compressed iron by monitoring atomic dynamics. / Jackson, Jennifer M.; Sturhahn, Wolfgang; Lerche, Michael; Zhao, Jiyong; Toellner, Thomas S.; Alp, E. Ercan; Sinogeikin, Stanislav V.; Bass, Jay D.; Murphy, Caitlin A.; Wicks, June K.

In: Earth and Planetary Science Letters, Vol. 362, 05.01.2013, p. 143-150.

Research output: Contribution to journalArticle

Jackson, JM, Sturhahn, W, Lerche, M, Zhao, J, Toellner, TS, Alp, EE, Sinogeikin, SV, Bass, JD, Murphy, CA & Wicks, JK 2013, 'Melting of compressed iron by monitoring atomic dynamics', Earth and Planetary Science Letters, vol. 362, pp. 143-150. https://doi.org/10.1016/j.epsl.2012.11.048
Jackson JM, Sturhahn W, Lerche M, Zhao J, Toellner TS, Alp EE et al. Melting of compressed iron by monitoring atomic dynamics. Earth and Planetary Science Letters. 2013 Jan 5;362:143-150. https://doi.org/10.1016/j.epsl.2012.11.048
Jackson, Jennifer M. ; Sturhahn, Wolfgang ; Lerche, Michael ; Zhao, Jiyong ; Toellner, Thomas S. ; Alp, E. Ercan ; Sinogeikin, Stanislav V. ; Bass, Jay D. ; Murphy, Caitlin A. ; Wicks, June K. / Melting of compressed iron by monitoring atomic dynamics. In: Earth and Planetary Science Letters. 2013 ; Vol. 362. pp. 143-150.
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