Stress-induced perovskite to post-perovskite transition inCaIrO3at room temperature

Abstract

Depending on how the compound is synthesized, both perovskite and post-perovskite phases of the ${\text{CaIrO}}_{3}$ can be obtained easily. However, a transition from the perovskite phase to the post-perovskite phase cannot be achieved under 30 GPa hydrostatic pressure at room temperature. By treating the perovskite sample in different pressure conditions from mostly hydrostatic pressure to uniaxial pressure and examining the residual strain in these samples with x-ray powder diffraction, we have shown that an irreversible transition from the perovskite phase to the post-perovskite phase occurs partially in the sample under a lattice shear stress at room temperature.