Showing papers by "Stanislav V. Sinogeikin published in 2000"
TL;DR: The single-crystal elastic properties of synthetic pyrope and periclase (MgO) have been measured by Brillouin scattering in a diamond anvil cell (DAC) up to 20 GPa as discussed by the authors.
241 citations
TL;DR: In this article, sound velocities and single-crystal elastic moduli of spinel-structured γ-Mg_2SiO_4 were measured to 873 K by Brillouin spectroscopy using a new high-temperature cell designed for singlecrystal measurements.
Abstract: The sound velocities and single-crystal elastic moduli of spinel-structured γ-Mg_2SiO_4 were measured to 873 K by Brillouin spectroscopy using a new high-temperature cell designed for single-crystal measurements. These are the first reported acoustic measurements of γ-Mg_2SiO_4 elasticity at high temperatures. A linear decrease of elastic moduli and sound velocities with temperature adequately describes the data. The adiabatic bulk modulus, K_S, shear modulus, μ, and respective temperature derivatives for γ-Mg_2SiO_4 are: K_S = 185(3) GPa, μ = 120.4(2.0) GPa, (∂K_S/∂T)_P = −0.024(3) GPa/K and (∂μ/∂T)_P = −0.015(2) GPa/K. Extrapolation of our data to transition zone pressures and temperatures indicates that the shear and compressional impedance contrasts associated with β- →γ-(Mg,Fe)_2SiO_4 transition are sufficient to produce an observable discontinuity at 520 km depth, even with a moderate (30–50%) amount of olivine.
90 citations
TL;DR: In this article, a compact ceramic high-temperature cell for Brillouin spectroscopy was designed and tested, which can be mounted onto a three- or four-circle goniometer and allows collection of the full set of elastic constants of minerals to temperatures in excess of 1500 K from samples with dimensions of 100×100×20 µm or smaller.
Abstract: A compact ceramic high-temperature cell for Brillouin spectroscopy was designed and tested. The cell can be mounted onto a three- or four-circle goniometer and allows collection of the full set of elastic constants of minerals to temperatures in excess of 1500 K from samples with dimensions of 100×100×20 µm or smaller. As a test of the instrument the single-crystal elastic constants of MgO were measured to 1510(10) K, and are found to be in excellent agreement with earlier independent results. The high-temperature cell should be useful for other types of spectroscopic measurements, and is especially useful in situations where spectral properties vary with the scattering geometry.
59 citations
TL;DR: The single-crystal elastic moduli of lawsonite [CaAl2(Si2O7)(OH)2·H2O] were measured by Brillouin spectroscopy at ambient conditions as discussed by the authors.
Abstract: The single-crystal elastic moduli of lawsonite [CaAl2(Si2O7)(OH)2·H2O] were measured by Brillouin spectroscopy at ambient conditions. The Voigt-Reuss-Hill averaged aggregate elastic moduli are K S = 125(2) GPa and μ = 52(2) GPa, for the adiabatic bulk modulus and shear modulus, respectively. Our acoustic results resolve discrepancies between the bulk moduli obtained in earlier compression studies. Lawsonite has distinctive acoustic properties, being characterized by extremely high shear elastic anisotropy (74%), a high V P to V S ratio ( V P/ V S = 1.94), and a large Poisson’s ratio (σ = 0.318).
42 citations
TL;DR: The bulk modulus of cubic majorite, one of the primary components of the Earth's transition zone, has been determined by two independent methods: quasi-hydrostatic compression in the diamond anvil cell and Brillouin spectroscopy at room pressure as discussed by the authors.
Abstract: The bulk modulus of a natural sample of cubic majorite, one of the primary components of the Earth's transition zone, has been determined by two independent methods: quasi-hydrostatic compression in the diamond anvil cell and Brillouin spectroscopy at room pressure. The two measurements agree well, and together yield a zero-pressure isothermal bulk modulus KOT = 162.7 (±3.3) GPa, and a pressure derivative KOT = 6.6 (±0.8). Additional compression experiments under nonhydrostatic conditions show that majorite supports shear stresses of at least 2 to 3 GPa at pressures of 7–11 GPa, among the highest values yet documented in silicates or oxides at comparable pressures. These results imply a high strength for majorite, suggesting that the transition zone could be strong to a degree that may influence deformation and heat transfer within the Earth.
29 citations
01 Jan 2000
TL;DR: In this paper, single-crystal elastic moduli of yttria have been measured by Brillouin spectroscopy up to 1200 C. The resulting bulk and shear moduli are K = 149.5 +/- 1.0 GPa and G(sub VRH) = 66.3 +/- 0.8 GPa, respectively.
Abstract: The single-crystal elastic moduli of yttria have been measured by Brillouin spectroscopy up to 1200 C. The room temperature values obtained are C11 = 223.6 +/- 0.6 GPa, C44 = 74.6 +/- 0.5 GPa, and C12 = 112.4 +/- 1.0 GPa. The resulting bulk and (Voigt-Reuss-Hill) shear moduli are K = 149.5 +/- 1.0 GPa and G(sub VRH) = 66.3 +/- 0.8 GPa, respectively. These agree much more closely with experimental values reported for polycrystalline samples than do previous single-crystal measurements. Linear least squares regressions to the variation of bulk and shear moduli with temperature result in derivatives of dK/dT = -17 +/- 2 MPa/degC and dG(sub VRH)/dT = -8 +/- 2 MPa/degC. Elastic anisotropy was found to remain essentially constant over the temperature range studied.