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Open Access Publications from the University of California

Scholarly Works (3 results)

  • Article
  • Peer Reviewed
UC Berkeley Previously Published Works (2006)

Cubic magnesiowustite has been deformed in a diamond anvil cell at room temperature. We present results for (Mg0.4Fe0.6)O, (Mg0.25Fe0.75)O, and (Mg0.1Fe0.9)O up to 37, 16, and 18 GPa, respectively. The diffraction images, obtained with the radial diffraction technique, are analyzed using both single peak intensities and a Rietveld method. For all samples, we observe a [100] fiber texture but the texture strength decreases with increasing iron content. This texture pattern is consistent with {110}-(1-10) slip. The images were also analyzed for stress, elastic strains, and elastic anisotropy. In general, the stress measured in magnesiowustite samples is lower than previously measured on MgO. The elastic anisotropy deduced from the X-ray measurements shows a broad agreement with models based on measurements with other techniques.

    Cover page: Texture development and elastic stresses in magnesiowustite at high pressure
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2017)
    We became aware of uncertainties about lattice parameters for osmium in Table 1 and B.K. Godwal (with the Department of Earth and Planetary Science at UC Berkeley) has reanalyzed the radial diamond anvil cell diffraction data, measured in situ at high pressure and compressive stress, with the Moment Pole Stress model in an advanced MAUD Rietveld technique (Wenk et al., 2014), taking into account lattice distortion under stress. [Table presented] The new results compare much better with data from hydrostatic experiments (Godwal et al., 2012). Since the emphasis of the paper was on mechanical twinning, we did not pay much attention to lattice distortion. Note that standard deviations are based on the Rietveld fit.
      Cover page: Corrigendum to “Significance of mechanical twinning in hexagonal metals at high pressure” [Acta Mater. 60 (2012) 430–442]
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2021)
      The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.
        Cover page: Novel experimental setup for megahertz X‐ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X‐ray Free‐Electron Laser (EuXFEL)Creative Commons 'BY' version 4.0 license
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