P-V-T equation of state of periclase from synchrotron radiation measurements

Agnès. Dewaele (1) , Guillaume Fiquet (1) , Denis Andrault (2) , Daniel Hausermann (3)

1 ENS de Lyon - École normale supérieure de Lyon
2 IPGP - Institut de Physique du Globe de Paris
3 ESRF - European Synchrotron Radiation Facility

The volume of periclase (MgO) has been measured by monochromatic X-ray diffraction in a laser-heated diamond anvil cell up to a pressure of 53 GPa and a temperature of 2500 K. The X-ray source was synchrotron radiation at the European Synchrotron Radiation Facility (Grenoble, France). In addition to laser heating, the use of argon as a pressure transmitting medium provided quasi-hydrostatic conditions in the cell assembly. In order to take thermal pressure effect into account, pressure was measured using an internal pressure calibrant (platinum). By analysis of the experimental P-V-T data set the following parameters were obtained: at ambient temperature, K'₀ = 3.94 ± 0.2 when K₀ is fixed to 161 GPa (with a Birch-Murnaghan equation of state); under high temperature, α(P = 0,T) = (3.0 + 0.0012T) × 10^-5 K^-1; (∂K_T/∂T)_P = -0.022(3) GPa K^-1. The quasi-harmonic Debye model appears to describe correctly the temperature dependence of the volume at high pressure within experimental errors, with the following parameters: θ_D0 = 800 K, γ₀ = 1.45 (Grüneisen parameter under ambient conditions), and q = 0.8 ± 0.5.

Mots clés: Mineral Physics: Equations of state; Mineral Physics: High-pressure behavior; Mineral Physics: X ray; neutron; and electron spectroscopy and diffraction

Domaines: Planète et Univers [physics]

Agnès. Dewaele, Guillaume Fiquet, Denis Andrault, Daniel Hausermann. P-V-T equation of state of periclase from synchrotron radiation measurements. Journal of Geophysical Research : Solid Earth, 2000, 105, pp.2869-2877. ⟨10.1029/1999JB900364⟩. ⟨insu-03596948⟩