HR: 17:00h
AN: DI44A-05 INVITED    [Abstracts]
TI: Anelastic behaviour of FexO at high pressure
AU: * Dubrovinsky, L
EM: Leonid.Dubrovinsky@uni-bayreuth.de
AF: BGI, University Bayreuth, Bayreuth, 95440, Germany
AU: Kantor, A
EM: Anastasia.Kantor@uni-bayreuth.de
AF: BGI, University Bayreuth, Bayreuth, 95440, Germany
AU: Kantor, I
EM: Innokenty.Kantor@uni-bayreuth.de
AF: BGI, University Bayreuth, Bayreuth, 95440, Germany
AU: Kurnosov, A
EM: Alexandr.Kurnosov@uni-bayreuth.de
AF: BGI, University Bayreuth, Bayreuth, 95440, Germany
AU: Krisch, M
EM: mkrisch@esrf.fr
AF: ESRF, 6 rue Jules Horowitz, Grenoble, 38000, France
AU: Bossak, A
EM: abossak@esrf.fr
AF: ESRF, 6 rue Jules Horowitz, Grenoble, 38000, France
AB: Elastic properties of solids are among the most important for solid Earth geophysics, engineering, and solid- state physics. Elastic moduli can be determined from pressure-volume relations (static or shock-wave compression), from acoustic waves velocity measurements (ultrasonic interferometry), or from dispersion curves of acoustic phonon branches (neutron, x-ray or light inelastic scattering). In the case of an ideal elastic solid the elastic moduli determined using different techniques should coincide within the experimental error (with the conversion factor between isothermal and adiabatic moduli). However, if any anelastic relaxation exists and the equilibrium strain for a given stress is achieved only after certain finite time interval, the effective elastic moduli measured by different methods would systematically vary, depending on sampling frequency. Anelasticity in a solid appears due to defects or other crystal imperfections when the energy minimum is achieved not only by varying the atomic geometry but also by changes in the materials' mesostructure (e.g. structure with a characteristic length larger than the crystal unit cell size). We have chosen non-stoichiometric FexO as a candidate for a strongly anelastic material. Although FexO has been intensively studied for several decades, many of its properties including elastic behaviour remain controversial and not well understood. A combined single-crystal inelastic x-ray scattering (IXS) and x-ray diffraction (XRD) study of synthetic wüstite Fe0.95O at elevated pressure revealed increasing the difference in the bulk modulus determined from static (XRD) and dynamic (IXS) measurements upon compression. We explain and quantitatively describe this observation by anelastic relaxation in wüstite. The reanalysis of previous results put some more evidence for relative good coincidence for bulk moduli and systematic difference for K' between static and dynamic measurements.
DE: 3620 Mineral and crystal chemistry (1042)
DE: 3630 Experimental mineralogy and petrology
DE: 3900 MINERAL PHYSICS
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
SC: Study of the Earth's Deep Interior [DI]
MN: 2007 Fall Meeting