Approaches to constrain single-crystal elastic properties from Brillouin scattering of polycrystalline samples

We have performed combined high pressure Brillouin scattering and X-ray diffraction of polycrystalline samples of MgO and of argon. We are able to reproduce the measured spatial dispersion of acoustic velocities and put constraints on the full elastic tensor by combining the texture, the density that we determine in situ and available elastic constants. The new approach of simultaneously determining density, preferred orientation and spatial dispersion of acoustic velocity of polycrystals promises to be a viable method to extract information on single-crystal (anisotropic) elastic properties of materials compressed to pressures at which single crystals cannot be preserved.