Perovskite-Type CuNbO3Exhibiting Unusual Noncollinear Ferrielectric to Collinear Ferroelectric Dipole Order Transition

Masayuki Fukuda, Ikuya Yamada, Hidenobu Murata, Hajime Hojo, Olivier J. Hernandez, Clemens Ritter, Katsuhisa Tanaka, Koji Fujita

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We report a perovskite oxide with a new type of polar structure, CuNbO3, thanks to the use of high-pressure and high-temperature synthesis. The perovskite-type CuNbO3 was previously obtained under high-pressure and high-temperature conditions, but its crystal structure has not been solved yet. Our structural analysis reveals that CuNbO3 perovskite crystallizes in a polar monoclinic space group (Pc) with a unit cell (apc being the pseudo-cubic lattice parameter), which is one maximal nonisomorphic subgroup of the polar rhombohedral space group, R3c. This compound exhibits a remarkable "noncollinear ferrielectric"structure due to parallel displacements of Cu+ and antiparallel displacements of Nb5+ along different axes, representing a new type of polar phase in the perovskite structure. We also observe that the noncollinear ferrielectric Pc structure transforms around 470 K into the collinear ferroelectric R3c structure that features parallel displacements of Cu+ and Nb5+ in the same direction. The present work extends the accessible composition range of the perovskite niobate series and demonstrates the role of A-O covalency in determining their crystal structures.

Original languageEnglish
Pages (from-to)5016-5027
Number of pages12
JournalChemistry of Materials
Issue number12
Publication statusPublished - Jun 23 2020

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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