Deformation microtextures in CaIrO3 post-perovskite under high stress conditions using a laser-heated diamond anvil cell

Abstract

Deformation microstructures of CaIrO3 post perovskite (PPv) in a laser heated diamond anvil cell (DAC) are examined using transmission electron microscopy. Under a high stress and strain rate in the deformation condition, a high density of the {110} twin domains were at first time observed in post perovskite structure, as well as [100] and [001] dislocations on the (010) plane. The exchange of the a-axis for the b-axes in the twin mechanism can reduce a stress in a single crystal at the beginning of the uniaxial compression. The {110} plane in PPv corresponds with that of the crystallographic preferred orientation that was previously reported in deformed MgSiO3 and MgGeO3 PPv in DACs. This result implies that the formation of the twin domains can play an important role in CaIrO3 PPv deformations under high stress and strain rate conditions (e.g., Deformation by DAC).