Phase transitions in the hexagonal tungsten bronze RbNbW2O9

Jason A. McNulty; Alexandra S. Gibbs; Philip Lightfoot; Finlay D. Morrison

doi:10.1016/j.jssc.2020.121275

Phase transitions in the hexagonal tungsten bronze RbNbW₂O₉

Jason A. McNulty, Alexandra S. Gibbs, Philip Lightfoot, Finlay D. Morrison

Research output: Contribution to journal › Article › peer-review

3 Citations (Scopus)

17 Downloads (Pure)

Abstract

The hexagonal tungsten bronze RbNbW₂O₉ is shown, by variable-temperature powder neutron diffraction and symmetry-mode analysis, to display a significantly different phase transition sequence compared to the related CsNbW₂O₉ composition. At ambient temperature, RbNbW₂O₉ adopts the polar orthorhombic space group Cmc2₁. Upon heating, the thermal evolution of the crystal structure proceeds via two transitions. These correspond to sequential loss of two distinct octahedral tilting modes, leading to space group P6₃mc at around 655K, and space group P6mm near 700 K. The polar distortion is retained up to the highest temperature studied here. The differences in structural behaviour between the proper ferroelectric RbNbW₂O₉ and the improper ferroelectric CsNbW₂O₉ emphasises the need for careful crystallographic analyses of materials of this type.

Original language	English
Article number	121275
Journal	Journal of Solid State Chemistry
Volume	286
Early online date	27 Feb 2020
DOIs	https://doi.org/10.1016/j.jssc.2020.121275
Publication status	Published - Jun 2020

Keywords

Powder neutron diffraction
Symmetry-mode analysis
Phase transitions
Hexagonal tungsten bronze
Proper ferroelectricity

Access to Document

10.1016/j.jssc.2020.121275

McNulty_2020_JSSC_RbNbW2O9_AAM
Copyright © 2020 Elsevier Inc. All rights reserved. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1016/j.jssc.2020.121275
Accepted author manuscript, 1.09 MBLicence: CC BY-NC-ND

Cite this

@article{bac3d98df343428c9ba0e36149c187d3,

title = "Phase transitions in the hexagonal tungsten bronze RbNbW2O9",

abstract = "The hexagonal tungsten bronze RbNbW2O9 is shown, by variable-temperature powder neutron diffraction and symmetry-mode analysis, to display a significantly different phase transition sequence compared to the related CsNbW2O9 composition. At ambient temperature, RbNbW2O9 adopts the polar orthorhombic space group Cmc21. Upon heating, the thermal evolution of the crystal structure proceeds via two transitions. These correspond to sequential loss of two distinct octahedral tilting modes, leading to space group P63mc at around 655K, and space group P6mm near 700 K. The polar distortion is retained up to the highest temperature studied here. The differences in structural behaviour between the proper ferroelectric RbNbW2O9 and the improper ferroelectric CsNbW2O9 emphasises the need for careful crystallographic analyses of materials of this type.",

keywords = "Powder neutron diffraction, Symmetry-mode analysis, Phase transitions, Hexagonal tungsten bronze, Proper ferroelectricity",

author = "McNulty, {Jason A.} and Gibbs, {Alexandra S.} and Philip Lightfoot and Morrison, {Finlay D.}",

note = "We thank the Science and Technology Facilities Council (STFC) for the provision of neutron diffraction facilities at ISIS (HRPD experiment RB1710021, https://doi.org/10.5286/ISIS.E.RB1710021) and the School of Chemistry, University of St Andrews for funding of a studentship to JAM through the EPSRC doctoral training grant (grant No. EP/K503162/1). ",

year = "2020",

month = jun,

doi = "10.1016/j.jssc.2020.121275",

language = "English",

volume = "286",

journal = "Journal of Solid State Chemistry",

issn = "0022-4596",

publisher = "Academic Press/Elsevier ",

}

TY - JOUR

T1 - Phase transitions in the hexagonal tungsten bronze RbNbW2O9

AU - McNulty, Jason A.

AU - Gibbs, Alexandra S.

AU - Lightfoot, Philip

AU - Morrison, Finlay D.

N1 - We thank the Science and Technology Facilities Council (STFC) for the provision of neutron diffraction facilities at ISIS (HRPD experiment RB1710021, https://doi.org/10.5286/ISIS.E.RB1710021) and the School of Chemistry, University of St Andrews for funding of a studentship to JAM through the EPSRC doctoral training grant (grant No. EP/K503162/1).

PY - 2020/6

Y1 - 2020/6

N2 - The hexagonal tungsten bronze RbNbW2O9 is shown, by variable-temperature powder neutron diffraction and symmetry-mode analysis, to display a significantly different phase transition sequence compared to the related CsNbW2O9 composition. At ambient temperature, RbNbW2O9 adopts the polar orthorhombic space group Cmc21. Upon heating, the thermal evolution of the crystal structure proceeds via two transitions. These correspond to sequential loss of two distinct octahedral tilting modes, leading to space group P63mc at around 655K, and space group P6mm near 700 K. The polar distortion is retained up to the highest temperature studied here. The differences in structural behaviour between the proper ferroelectric RbNbW2O9 and the improper ferroelectric CsNbW2O9 emphasises the need for careful crystallographic analyses of materials of this type.

AB - The hexagonal tungsten bronze RbNbW2O9 is shown, by variable-temperature powder neutron diffraction and symmetry-mode analysis, to display a significantly different phase transition sequence compared to the related CsNbW2O9 composition. At ambient temperature, RbNbW2O9 adopts the polar orthorhombic space group Cmc21. Upon heating, the thermal evolution of the crystal structure proceeds via two transitions. These correspond to sequential loss of two distinct octahedral tilting modes, leading to space group P63mc at around 655K, and space group P6mm near 700 K. The polar distortion is retained up to the highest temperature studied here. The differences in structural behaviour between the proper ferroelectric RbNbW2O9 and the improper ferroelectric CsNbW2O9 emphasises the need for careful crystallographic analyses of materials of this type.

KW - Powder neutron diffraction

KW - Symmetry-mode analysis

KW - Phase transitions

KW - Hexagonal tungsten bronze

KW - Proper ferroelectricity

UR - https://doi.org/10.1016/j.jssc.2020.121548

U2 - 10.1016/j.jssc.2020.121275

DO - 10.1016/j.jssc.2020.121275

M3 - Article

SN - 0022-4596

VL - 286

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

M1 - 121275

ER -

Phase transitions in the hexagonal tungsten bronze RbNbW₂O₉

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

New Horizon in Nanoscale: Ferrolectric, Ferroelastic and Multiferroic Domain Walls: a New Horizon in Nanoscale Functional Materials