HR: 16:45h
AN: V32G-04    [PDF]
TI: Study of Sound Velocities of Iron With Nuclear Resonant Inelastic X-ray Scattering Under High Pressure and Temperature
AU: * Lin, J
EM: j.lin@gl.ciw.edu
AF: Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington DC, DC 20015 United States
AU: Sturhahn, W
EM: sturhahn@aps.anl.gov
AF: Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 United States
AU: Zhao, J
EM: jzhao@aps.anl.gov
AF: Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 United States
AU: Shen, G
EM: shen@cars.uchicago.edu
AF: The University of Chicago, 9700 South Cass Avenue, Argonne, IL 60439 United States
AU: Mao, H
EM: mao@gl.ciw.edu
AF: Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington DC, DC 20015 United States
AU: Hemley, R J
EM: hemley@gl.ciw.edu
AF: Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington DC, DC 20015 United States
AB: Iron is the most important component in the Earth's core. Understanding its physical properties under high pressures and high temperatures is crucial for interpreting and constraining geophysical and geochemical models. We have built a double-sided YLF laser heating system to study iron with nuclear resonant inelastic x-ray scattering technique under simultaneously high pressures and high temperatures. Inelastic x-ray scattering spectra of hcp-Fe have been collected up to approximately 58 GPa and 1500 K in a laser-heated diamond anvil cell. Temperature-dependent inelastic x-ray spectra provide independent temperature measurement of the laser-heated iron, in which the measured temperatures were in fairly good agreement with temperatures measured from thermal radiation spectra fitted to Planck radiation function. This independent temperature measurement of the laser-heated sample confirms the validity of temperatures determined from Planck radiation law in the laser-heated diamond anvil cell experiments. Sound velocities of hcp-Fe are obtained from the measured phonon density of states up to approximately 58 GPa and 1500 K. The compressional and shear wave velocity of hcp-Fe decrease with increasing temperature under high pressures. Our results for the compressional and shear wave velocity of hcp-Fe show that the compressional and shear wave velocity are not linearly related to the density at high temperatures and pressures. This study also provides a new technique of measuring the melting curve of iron under extreme pressures.
DE: 3600 MINERALOGY AND PETROLOGY (replaces
DE: 3900 MINERAL PHYSICS
DE: 3924 High-pressure behavior
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
DE: 5100 PHYSICAL PROPERTIES OF ROCKS
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting