Single-crystal elastic properties of (Mg0.987, Fe0.013) O to 9 GPa

Hanni J. Reichmann, S. V. Sinogeikin, J. D. Bass

Research output: Contribution to journalArticle

Abstract

The single-crystal elastic moduli of (Mg0.987, Fe0.013)O were measured by Brillouin spectroscopy in a diamond-anvil cell at high pressures to 9 GPa at room temperature. The ambient-pressure single-crystal elastic moduli are (1) C11 = 291.2(3.0) GPa; (2) C12= 96.1(2.0) GPa; and (3) C'44 = 151.9(2.0) GPa. From the single-crystal moduli, the aggregate elastic moduli are calculated to be adiabatic bulk modulus Kso = 161.1(3.0) GPa, the Voigt bound of the shear modulus is Gv = 130.0(2.0), and the Reuss bound GR = 124.2(2.0) GPa, giving a Voigt-Reuss-Hill average G = 127.1(2.0) GPa. We find that the addition of 1.3 mol% of Fe has a surprisingly large effect on the aggregate shear modulus, decreasing the room-pressure value by 2.4% as compared to Brillouin data for periclase (MgO) measured with the same technique. The adiabatic bulk modulus also decreases by 1.3%, although this decrease is within the mutual uncertainties of the measurements. Our results confirm significant non-linearity in single-crystal elastic moduli C11 and C44 and the aggregate shear modulus G of magnesiowütite in the Mg-rich end. The pressure derivative of the bulk modulus K's = 4.2(2), as determined by a third-order finite-strain fit, is about 9% higher than the Brillouin results for the MgO end-member, whereas the pressure dependence of the shear modulus G'= 23(l) is found to be identical to that of periclase. The measurements demonstrate that even a small amount of Fe (1.3 mol%) has a measurable effect on the elastic properties of MgO-FeO solid solutions.

Original languageEnglish (US)
Pages (from-to)1306-1311
Number of pages6
JournalAmerican Mineralogist
Volume93
Issue number8-9
DOIs
StatePublished - Aug 1 2008

Keywords

  • Brillouin interferometry
  • Elastic properties
  • High press
  • Magnesiowüstite

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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