Unprecedented phase transition sequence in the perovskite Li_0.2Na_0.8NbO₃.

ABSTRACT: The perovskite Li_0.2Na_0.8NbO₃ is shown, by powder neutron diffraction, to display a unique sequence of phase transitions at elevated temperature. The ambient temperature polar phase (rhombohedral, space group R3c) transforms via a first-order transition to a polar tetragonal phase (space group P4₂mc) in the region 150-300°C; these two phases correspond to Glazer tilt systems a^-a^-a^- and a⁺a⁺c^-, respectively. At 500°C a ferroelectric-paraelectric transition takes place from P4₂mc to P4₂/nmc, retaining the a⁺a⁺c^-

SUBMITTER: Dixon CAL 

PROVIDER: S-EPMC5414396 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature