CALL FOR PROPOSALS:

ORGANIZERS

  • Harvey Thorleifson, Chair
    Minnesota Geological Survey
  • Carrie Jennings, Vice Chair
    Minnesota Geological Survey
  • David Bush, Technical Program Chair
    University of West Georgia
  • Jim Miller, Field Trip Chair
    University of Minnesota Duluth
  • Curtis M. Hudak, Sponsorship Chair
    Foth Infrastructure & Environment, LLC

 

Paper No. 11
Presentation Time: 11:05 AM

THE ELASTIC PROPERTIES OF FINE-GRAINED POLYCRYSTALLINE SAMPLES BY BRILLOUIN SCATTERING


ZHANG, Guimiao1, BÉJINA, Frédéric2, BYSTRICKY, Misha2, ZHANG, Jin S.1, LIEBERMANN, Robert C.3, GWANMESIA, Gabriel4 and BASS, Jay D.5, (1)Department of Geology, University of Illinois at Urbana-Champaign, 1301 W Green St, Urbana, IL 61801, (2)Institut de Recherche en Astrophysique et Planétologie Observatoire Midi-Pyrénées, 14 Avenue Edouard Belin, Toulouse, 31400, France, (3)Compres, Room 167 ESS Building, Stony Brook, NY 11794, (4)Dept. of Physics, Delaware State University, 1200 N. DuPont Highway, Dover, DE 19901, (5)Geology, COMPRES, and University of Illinois Urbana-Champaign, 1301 West Green St, Urbana, IL 61822, guimiao.zhang@gmail.com

The crust and mantle of the Earth are polycrystalline in nature, whereas in the laboratory we often measure properties on near-perfect single crystals when available. The relationship between the properties of single-crystal and polycrystalline samples is therefore of fundamental importance in applying lab measurements to the Earth. In this study we have investigated the sound velocities and elastic properties of fine-grained polycrystalline materials using Brillouin scattering. Our initial experiments were performed on polycrystalline MgO with a grain size of approximately a few microns or less. Samples were prepared using spark plasma sintering, resulting in dense fine-grained material that is sufficiently transparent to transmit the visible light used in Brillouin scattering. Samples were ground and polished into plate-like shapes for symmetric geometry Brillouin scattering at room conditions, and also at high pressure using a diamond anvil cell. Brillouin spectra from these samples show broad peaks that are roughly symmetric in shape. Our results thus far indicate that the velocities of the fine-grained material are consistent with the velocities obtained from single-crystal measurements using Voigt-Reuss-Hill averaging.
Meeting Home page GSA Home Page