ISIS Neutron and Muon Source Data Journal

Tetrahedral tumbling in the giant barocaloric ammonium sulfate

Abstract: Ammonium sulfate is a deceptively simple hydrogen-bonded inorganic salt. It has attracted intense interest, originally for its ferroelectricity and recently for its barocaloric effect; both of these properties arise from a phase transition at -50 ºC. We recently undertook a comprehensive study of the dynamics of this system under pressure, using both inelastic and quasielastic scattering. Our QENS results indicate that the major hopping motion corresponds to tumbling of the tetrahedral ammonium ions, which intriguingly increases in frequency with applied pressure. However, definitive analysis has been hampered by the fact that we initially relied on a previously collected resolution function that proved inadequate, and by the lack of data at high Q, where different models differ most. Here we request a single day on OSIRIS to complete this experiment.

Principal Investigator: Dr Anthony Phillips
Experimenter: Dr Helen Walker
Local Contact: Dr Franz Demmel
Experimenter: Miss Bernet Meijer

DOI: 10.5286/ISIS.E.RB2000267

ISIS Experiment Number: RB2000267

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Dr Anthony Phillips et al; (2021): Tetrahedral tumbling in the giant barocaloric ammonium sulfate, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2000267

Data is released under the CC-BY-4.0 license.