Abstract
The post-perovskite (pPv) is the high-pressure phase of some highly distorted perovskites. The pPv phase of MgSi stabilized under 125 GPa and 2000 K cannot be quenched to ambient pressure. In contrast, the pPv CaIr can be synthesized under a modest pressure or even at ambient pressure. However, the pPv CaIr has not been fully characterized. We report here systematic structural studies, measurements of transport and magnetic properties including critical phenomena, specific heat, and thermal conductivity in a series of samples CaSrIr synthesized under high pressure. The CaSrIr samples exhibit an evolution from the pPv phase to the perovskite phase. We have also prepared the perovskite (Pv phase) CaIr with the wet chemical method. Rietveld refinements of the pPv and Pv phase CaIr have been made based on high-resolution synchrotron diffraction. In comparison with effects of the chemical substitution on the crystal structure and physical properties, we have studied the structure and magnetic properties of the pPv CaIr under hydrostatic pressure. Results have been discussed in the context of orbital ordering biased on the intrinsic structural distortion and the strong spin-orbit coupling that is much enhanced in these 5 oxides with the pPv structure.
12 More- Received 27 March 2010
DOI:https://doi.org/10.1103/PhysRevB.83.064401
©2011 American Physical Society