HR: 17:05h
AN: MR44A-04    [Abstracts]
TI: Interrelation Between Elastic Properties Determined by Brillouin Spectroscopy and Thermal Transport Properties of Garnets
AU: * Marquardt, H
EM: hama@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Division 5.1, Telegrafenberg, Potsdam, 14473, Germany
AU: Speziale, S
AF: GeoForschungsZentrum Potsdam, Division 4.1, Telegrafenberg, Potsdam, 14473, Germany
AU: Schilling, F
AF: GeoForschungsZentrum Potsdam, Division 5.1, Telegrafenberg, Potsdam, 14473, Germany
AB: Both thermal diffusivity and elastic constants are mineral properties of major relevance to understand the dynamics of the solid earth. It is expected that a relation between sound wave velocities, elastic constants, and thermal transport properties exist. The goal of this study is to improve our understanding of the correlation between elastic properties, thermal transport properties and the mean free path lengths of phonons. We are determining the entire set of elastic constants of different synthetic and natural garnets, for instance the solid solution series Y₃Al₅O₁₂-Yb₃Al₅O₁₂, with the recently installed Brillouin scattering system at the GeoForschungsZentrum Potsdam. This system consists of a Nd:YVO₄ solid state Laser with a wavelength of 532 nm as light source and a Sandercock-type tandem multipass Fabry-Perot interferometer equipped with a photomultiplier tube for signal detection as spectrometer. All measurements were performed in a 90 degree symmetric forward scattering geometry. An anisotropy in shear sound wave velocities of about 3 % and an anisotropy in compressional sound wave velocity of about 1 % is observed for the Yb-rich garnets, which is in agreement with literature data for Y₃Al₅O₁₂. We reported the thermal diffusivity of the same garnet single crystals in a previous study using a transient method^[1]. Knowledge of both the elastic constants and the thermal diffusivities allows the calculation of the mean free path lengths of phonons. [1] Schilling, F. R. (1999): Eur. J. Mineral. 11, 1115-1124
DE: 3909 Elasticity and anelasticity
DE: 3934 Optical, infrared, and Raman spectroscopy
DE: 3999 General or miscellaneous
DE: 5134 Thermal properties
DE: 5139 Transport properties
SC: Mineral and Rock Physics [MR]
MN: 2007 Joint Assembly