ISIS Neutron and Muon Source Data Journal
This is a page describing data taken during an experiment at the ISIS Neutron and Muon Source. Information about the ISIS Neutron and Muon Source can be found at https://www.isis.stfc.ac.uk.
Magnetic excitations in complex osmate La7Os3O18
Abstract: This project will investigate an unusual magnetic material called La7Os3O18. In many magnets magnetic moments order fully when cooled below their transition temperature. La7Os3O18 does not behave so simply. It shows a magnetic transition at about 43 K, but heat capacity and magnetic susceptibility measurements suggest that a significant magnetic component remains partly disordered or fluctuating at lower temperatures. A key puzzle is that the material releases much less magnetic entropy than expected. Entropy reflects the number of possible arrangements of atomic magnetic moments, so this missing entropy suggests that the moments do not fully settle into a conventional ordered state. Our recent neutron diffraction experiments show that part of the material forms long-range magnetic order, but they cannot reveal the nature of the remainder. This experiment will use neutron spectroscopy on the LET instrument to measure magnetic excitations in a powder sample of La7Os3O18. Measurements from very low temperature to above the magnetic transition will show how the behaviour changes and whether ordered and fluctuating magnetism coexist. The results will help explain the missing entropy and identify the best model for magnetism in La7Os3O18. The work will improve understanding of complex quantum magnetic materials, where competing interactions can produce behaviour more complicated than observed in conventional magnets.
Principal Investigator: Dr Alexandra Gibbs
Experimenter: Mr Juntian Peng
Experimenter: Mr Diogo Alexandre Fernandes De Almeida
Local Contact: Dr Duc Le
Experimenter: Dr Andreas Rost
Experimenter: Mr Ashley Brennan
Experimenter: Dr George Wood
Experimenter: Dr Maximilian Pelly
DOI: 10.5286/ISIS.E.RB2620893
ISIS Experiment Number: RB2620893
| Part DOI | Instrument | Public release date | Download Link |
|---|---|---|---|
| 10.5286/ISIS.E.RB2620893-1 | MARI | 21 October 2029 | Download |
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 Alexandra Gibbs et al; (2026): Magnetic excitations in complex osmate La7Os3O18, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2620893
Data is released under the CC-BY-4.0 license.
