Pressure Tuning the Jahn-Teller Transition Temperature in NaNiO₂.

ABSTRACT: NaNiO₂ is a layered material consisting of alternating layers of NaO₆ and Jahn-Teller-active NiO₆ edge-sharing octahedra. At ambient pressure, it undergoes a broad phase transition from a monoclinic to rhombohedral structure between 465 and 495 K, associated with the loss of long-range orbital ordering. In this work, we present the results of a neutron powder diffraction study on powdered NaNiO₂ as a function of pressure and temperature from ambient pressure to ∼5 GPa between 290 and 490 K. The 290 and 460 K isothermal compressions remained in the monoclinic phase up to the maximum pressures studied, whereas the 490 K isotherm was mixed-phase throughout. The unit-cell volume was fitted to a second-order Birch-Murnaghan equation of state, where

SUBMITTER: Nagle-Cocco LAV 

PROVIDER: S-EPMC9098164 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature