ISIS Neutron and Muon Source Data Journal

Phonon Anomalies in YMnO3 at High Temperature

Abstract: The reported structural phase transition in YMnO3 from P63cm to P63/mmc space group occurs at 1258 ±14 K. For low temperature phase (space group P63cm) the phonon modes are found to be stable (Fig. 2) in the entire Brillouin zone. However, we find unstable phonon mode in the high temperature (space group P63/mmc) phases at M (0.5 0 0) and K (1/3 1/3 0) points. These unstable modes are highly anharmonic in nature and become stable at higher temperature due to anharmonicity. The transition from ferroeletric (space group P63cm) to paraelectric phase ((space group P63/mmc)) is expected to be driven by phonon anomalies. The low energy phonon modes up to 20 meV are expected to be most affected by the phase transitions. We propose to measure temperature dependence of low energy zone centre and zone boundary phonon modes from 300 K and 1300 K.

Principal Investigator: Dr Ranjan Mittal
Experimenter: Dr Sanjay Kumar Mishra
Experimenter: Dr Samrath Lal Chaplot
Experimenter: Dr Mayanak Kumar Gupta
Experimenter: Dr Devashi Adroja
Experimenter: Professor Je-Geun Park
Experimenter: Ms Hasung Sim

DOI: 10.5286/ISIS.E.RB1520143

ISIS Experiment Number: RB1520143

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
Select the data format above to find out more about it.

Data Citation

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

For Example:
Dr Ranjan Mittal et al; (2015): Phonon Anomalies in YMnO3 at High Temperature , STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB1520143

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