Measured elastic moduli of single-crystal MgO up to 1800 K

TLDR: In this article, the authors measured the temperature dependence of the adiabatic elastic moduli of single-crystal MgO over the temperature range 300-1800 K. The high temperature limit of their measurements extends by 500 K the upper limit over which elasticity data on MgOs are now available.

Abstract: Using the rectangular parallelepiped resonance method we measured the temperature dependence of the adiabatic elastic moduli of single-crystal MgO over the temperature range 300–1800 K. The high temperature limit of our measurements extends by 500 K the upper limit over which elasticity data on MgO are now available. Although our measured temperature dependence of C ij s are generally in good agreement with previous measurements over a more narrow range in temperature, we found that C 44 s decreases more rapidly with temperature, for T > 1000 K, than previous studies suggest. We also found that each of the slopes (ϱC 11 s /ϱT)p, (ϱKs/ϱT)p, and (C 44 s /ϱT)p become less negative with increasing temperature for T > 1400 K. From our measurements on elasticity we are able to confirm that the Gruneisen parameter at zero pressure is nearly constant with temperature up to 1800 K, with only a slight decrease above 1000 K. Utilizing our new data we present calculations showing the temperature dependence of thermodynamic parameters important in studies of earth's interior.