Plastic Deformations and Lattice Preferred Orientations in Post-Perovskite-type MgGeO₃ Using a Diamond Anvil Cell

Abstract

X-ray diffraction (XRD) measurement in radial geometry using a diamond anvil cell (DAC) and synchrotron radiation is a powerful tool to investigate lattice preferred orientations (LPO) of high-pressure materials such as post-perovskite (PPv) -type phases. Recent experimental and theoretical reports about LPO of PPv-type phases and problems of deformation experiments were reviewed in this article. Our results of radial and axial XRD measurements and deformation experiments on MgGeO₃-PPv were shown also. When the MgGeO₃-PPv was formed in DAC, it had strong LPO from the beginning even before making the plastic deformation and the LPO changed depending on the pre-phase before the transformation. Pressure variation of axial diffraction patterns of MgGeO₃-PPv during plastic deformation were obtained for the first time by using a diamond gasket technique.