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

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 CaIrO ₃ PPv deformations under high stress and strain rate conditions (e.g., Deformation by DAC).