An electronically driven improper ferroelectric: tungsten bronzes as microstructural analogs for the hexagonal manganites

Jason A. McNulty, T. Thao Tran, P. Shiv Halasyamani, Shane McCartan, Ian MacLaren, Alexandra Gibbs, Felicia Lim, Patrick Turner, J. Marty Gregg, Philip Lightfoot, Finlay D. Morrison

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)
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Abstract

Since the observation that the properties of ferroic domain walls (DWs) can differ significantly from the bulk materials in which they are formed, it has been realized that domain wall engineering offers exciting new opportunities for nanoelectronics and nanodevice architectures. Here, a novel improper ferroelectric, CsNbW2O9, with the hexagonal tungsten bronze structure, is reported. Powder neutron diffraction and symmetry mode analysis indicate that the improper transition (TC = 1100 K) involves unit cell tripling, reminiscent of the hexagonal rare earth manganites. However, in contrast to the manganites the symmetry breaking in CsNbW2O9 is electronically driven (i.e., purely displacive) via the second-order Jahn-Teller effect in contrast to the geometrically-driven tilt mechanism of the manganites. Nevertheless CsNbW2O9 displays the same kinds of domain microstructure as those found in the manganites, such as the characteristic six-domain "cloverleaf" vertices and DW sections with polar discontinuities. The discovery of a completely new material system, with domain patterns already known to generate interesting functionality in the manganites, is important for the emerging field of DW nanoelectronics.
Original languageEnglish
Article number1903620
Number of pages9
JournalAdvanced Materials
Volume31
Issue number40
Early online date7 Aug 2019
DOIs
Publication statusPublished - 4 Oct 2019

Keywords

  • Improper ferroelectricity
  • Ferroelectrics
  • Domain walls
  • Structure-property relationships

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