In situ observation of shear stress-induced perovskite to post-perovskite phase transition in CaIrO 3 and the development of its deformation texture in a diamond-anvil cell up to 30GPa

Ken Niwa, Nobuyoshi Miyajima, Yusuke Seto, Kenya Ohgushi, Hirotada Gotou, Takehiko Yagi

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

The perovskite (Pv) to post-perovskite (PPv) phase transition and the deformation texture of the PPv phase were investigated on the basis of a high-pressure X-ray diffraction (XRD) study of CaIrO 3 using a diamond-anvil cell in a pressure range up to 31GPa. The development of a crystallographic preferred orientation (CPO) in the PPv phase was observed after the plastic deformation from 8 or 9GPa to 31GPa at both room and high (∼1500K) temperatures. The observed CPOs in the present study indicate that the (010) plane worked as an active slip plane in the PPv phase over the entire pressure and temperature range of the present experiment. We also confirmed that the Pv to PPv phase transition proceeds at room temperature under high-stress conditions. The phase transition under high-stress condition is in stark contrast to the results of a previous hydrostatic experiment in which the Pv-CaIrO 3 remained stable in a helium media at 31GPa and room temperature. This indicates that shear stress plays an important role in the Pv to PPv phase transition, and this effect should be taken into account when the thermal structure at the D' layer is discussed on the basis of the high-pressure experiments.

Original languageEnglish
Pages (from-to)10-17
Number of pages8
JournalPhysics of the Earth and Planetary Interiors
Volume194-195
DOIs
Publication statusPublished - 2012 Mar 1
Externally publishedYes

Keywords

  • Diamond-anvil cell
  • Lattice preferred orientation
  • Perovskite
  • Phase transition
  • Post-perovskite
  • Shear stress

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science

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