T147 Earth's Deep Interior: In Honor of Motohiko Murakami, 2011 MSA Awardee
Tuesday, 11 October 2011
8:00 AM - 12:00 PM
Room 102BC
THE ELASTIC PROPERTIES OF FINE-GRAINED POLYCRYSTALLINE SAMPLES BY BRILLOUIN SCATTERING
Paper number: T147-13
Program: Technical Sessions
Time: 11:05 AM – 11:20 AM
Authors
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Frédéric BéjinaInstitut de Recherche en Astrophysique et Planétologie Observatoire Midi-Pyrénées, Toulouse, N/A
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Misha BystrickyInstitut de Recherche en Astrophysique et Planétologie Observatoire Midi-Pyrénées, Toulouse, N/A
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Jin S. ZhangUniversity of Illinois at Urbana-Champaign, Urbana, IL
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Robert C. LiebermannStony Brook, NY
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Gabriel GwanmesiaDelaware State University, Dover, DE
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Jay D. BassCOMPRES, and University of Illinois Urbana-Champaign, Urbana, IL
Abstract
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.