title: Single-crystal synchrotron X-ray diffraction study of wüstite and magnesiowüstite at lower-mantle pressures.
abstract: This study demonstrates the use of monochromatic synchrotron X-ray radiation of 40 keV for high-precision equation-of-state studies on sets of single crystals analysed individually in the same diamond-anvil pressure cell. Angle-dispersive zone-axis diffraction patterns were obtained from crystals of wustite-Fe0.93O and magnesiowüstite-(Mg0.73Fe0.27)O to 51 GPa in a hydrostatic helium pressure medium. The rhombohedral phase of Fe0.93O was observed above 23 GPa, and its isothermal bulk modulus (K0) was determined to be 134 (+/-4) GPa, assuming K'=4. The rhombohedral phase of Fe(0.93)O is more compressible than B1-structured Fe0.93O, with K0=146 (+/-2) GPa. Magnesiowüstite-(Mg0.73Fe0.27)O remains cubic over the experimental pressure range, and has a bulk modulus of 154 (+/-3) GPa with K'=4.0 (+/-0.1).
authors.affiliation: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC 20015, USA. s.jacobsen@gl.ciw.edu
authors.forename: Steven D
authors.initials: SD
authors.lastname: Jacobsen
authors.forename: Jung Fu
authors.initials: JF
authors.lastname: Lin
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Angel
authors.forename: Guoyin
authors.initials: G
authors.lastname: Shen
authors.forename: Vitali B
authors.initials: VB
authors.lastname: Prakapenka
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Dera
authors.forename: Ho-kwang
authors.initials: HK
authors.lastname: Mao
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Hemley