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Elasticity of single crystal and polycrystalline MgSiO 3 perovskite by Brillouin spectroscopy
Author(s) -
Sinogeikin Stanislav V.,
Zhang Jianzhong,
Bass Jay D.
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl019559
Subject(s) - brillouin spectroscopy , crystallite , elastic modulus , materials science , anisotropy , elasticity (physics) , bulk modulus , single crystal , shear modulus , brillouin scattering , mineralogy , young's modulus , resonant ultrasound spectroscopy , perovskite (structure) , crystallography , composite material , optics , chemistry , physics , metallurgy , optical fiber
The elastic moduli of MgSiO 3 perovskite have been measured on both single‐crystal and polycrystalline samples by Brillouin spectroscopy at ambient conditions. The aggregate elastic moduli calculated from measured single‐crystal elastic moduli and from the average polycrystalline velocities are in excellent agreement. This convincingly demonstrates that accurate values of elastic moduli can be obtained for polycrystalline samples of dense anisotropic materials by Brillouin spectroscopy. Our new values of the bulk modulus (K S = 253(3) GPa) and shear modulus (μ = 175(2) GPa) are ∼4% and ∼1% lower than commonly accepted values for end‐member MgSiO 3 perovskite (K S = 264 GPa, μ = 177 GPa). These lower elastic moduli suggest that the pressure, temperature, and compositional dependence of elastic moduli and wave velocities for magnesian silicate perovskite must be reevaluated in order to obtain reliable constraints on the mantle chemistry and thermal structure.