Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3
The perovskite Li0.2Na0.8NbO3 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...
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International Union of Crystallography
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doaj-24498a21332b487b828f50a0f2020ed62020-11-24T22:37:14ZengInternational Union of CrystallographyIUCrJ2052-25252017-05-014321522210.1107/S2052252517002226fc5017Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3Charlotte A. L. Dixon0Jason A. McNulty1Steven Huband2Pamela A. Thomas3Philip Lightfoot4School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST, ScotlandSchool of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST, ScotlandDepartment of Physics, University of Warwick, Coventry CV4 7AL, EnglandDepartment of Physics, University of Warwick, Coventry CV4 7AL, EnglandSchool of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST, ScotlandThe perovskite Li0.2Na0.8NbO3 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− tilt. Transformation to a single-tilt system, a0a0c+ (space group P4/mbm), occurs at 750°C, with the final transition to the aristotype cubic phase at 850°C. The P42mc and P42/nmc phases have each been seen only once and twice each, respectively, in perovskite crystallography, in each case in compositions prepared at high pressure.http://scripts.iucr.org/cgi-bin/paper?S2052252517002226perovskiteferroelectricpowder neutron diffraction |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Charlotte A. L. Dixon Jason A. McNulty Steven Huband Pamela A. Thomas Philip Lightfoot |
spellingShingle |
Charlotte A. L. Dixon Jason A. McNulty Steven Huband Pamela A. Thomas Philip Lightfoot Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3 IUCrJ perovskite ferroelectric powder neutron diffraction |
author_facet |
Charlotte A. L. Dixon Jason A. McNulty Steven Huband Pamela A. Thomas Philip Lightfoot |
author_sort |
Charlotte A. L. Dixon |
title |
Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3 |
title_short |
Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3 |
title_full |
Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3 |
title_fullStr |
Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3 |
title_full_unstemmed |
Unprecedented phase transition sequence in the perovskite Li0.2Na0.8NbO3 |
title_sort |
unprecedented phase transition sequence in the perovskite li0.2na0.8nbo3 |
publisher |
International Union of Crystallography |
series |
IUCrJ |
issn |
2052-2525 |
publishDate |
2017-05-01 |
description |
The perovskite Li0.2Na0.8NbO3 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− tilt. Transformation to a single-tilt system, a0a0c+ (space group P4/mbm), occurs at 750°C, with the final transition to the aristotype cubic phase at 850°C. The P42mc and P42/nmc phases have each been seen only once and twice each, respectively, in perovskite crystallography, in each case in compositions prepared at high pressure. |
topic |
perovskite ferroelectric powder neutron diffraction |
url |
http://scripts.iucr.org/cgi-bin/paper?S2052252517002226 |
work_keys_str_mv |
AT charlottealdixon unprecedentedphasetransitionsequenceintheperovskiteli02na08nbo3 AT jasonamcnulty unprecedentedphasetransitionsequenceintheperovskiteli02na08nbo3 AT stevenhuband unprecedentedphasetransitionsequenceintheperovskiteli02na08nbo3 AT pamelaathomas unprecedentedphasetransitionsequenceintheperovskiteli02na08nbo3 AT philiplightfoot unprecedentedphasetransitionsequenceintheperovskiteli02na08nbo3 |
_version_ |
1725718107299774464 |