A New Cation-Ordered Structure Type with Multiple Thermal Redistributions in Co₂ InSbO₆.

ABSTRACT: Cation ordering in solids is important for controlling physical properties and leads to ilmenite (FeTiO₃ ) and LiNbO₃ type derivatives of the corundum structure, with ferroelectricity resulting from breaking of inversion symmetry in the latter. However, a hypothetical third ABO₃ derivative with R32 symmetry has never been observed. Here we show that Co₂ InSbO₆ recovered from high pressure has a new, ordered-R32 A₂ BCO₆ variant of the corundum structure. Co₂ InSbO₆ is also remarkable for showing two cation redistributions, to (Co_0.5 In_0.5 )₂ CoSbO₆ and then Co₂ InSbO₆ variants of the ordered-LiNbO₃ A₂ BCO₆ structure on heating. The cation distributions change magnetic properties as the final ordered-LiNbO₃ product has a sharp ferrimagnetic transition unlike the initial ordered-R32 phase. Future syntheses of metastable corundum derivatives at pressure are likely to reveal other cation-redistribution pathways, and may enable ABO₃ materials with the R32 structure to be discovered.

SUBMITTER: Ji K 

PROVIDER: S-EPMC9321074 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature