Equation of state of cubic boron nitride at high pressures and temperatures

Frédéric Datchi (1) , Agnès Dewaele (2) , Yann Le Godec (1) , Paul Loubeyre (2)

1 IMPMC - Institut de minéralogie et de physique des milieux condensés
2 DPTA - Département de Physique Théorique et Appliquée

We report accurate measurements of the equation of state (EOS) of cubic boron nitride by x-ray diffraction up to 160 GPa at 295 K and 80 GPa in the range 500-900 K. Experiments were performed on single-crystals embedded in a quasi-hydrostatic pressure medium (helium or neon). Comparison between the present EOS data at 295 K and literature allows us to critically review the recent calibrations of the ruby standard. The full P-V-T data set can be represented by a Mie-Grüneisen model, which enables us to extract all relevant thermodynamic parameters: bulk modulus and its first pressure-derivative, thermal expansion coefficient, thermal Grüneisen parameter and its volume dependence. This equation of state is used to determine the isothermal Grüneisen mode parameter of the Raman TO band. A new formulation of the pressure scale based on this Raman mode, using physically-constrained parameters, is deduced.

Mots clés: cubic boron nitride; equation of state; thermal effects; pressure scale

Domaines: Autre [cond-mat.other]; Minéralogie

Frédéric Datchi, Agnès Dewaele, Yann Le Godec, Paul Loubeyre. Equation of state of cubic boron nitride at high pressures and temperatures. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007, 75, pp.214104. ⟨10.1103/PhysRevB.75.214104⟩. ⟨hal-00133821⟩