ISIS Neutron and Muon Source Data Journal

Single crystal neutron diffraction determination of U6Fe Structure

Abstract: U6Fe is an interesting superconductor with an exceptionally high critical field of 12 T and a superconducting transition temperature of 4K, the highest known for a uranium-based heavy-fermion superconductor, where neither the Pauli nor usual BCS orbital limit is apparently respected. Previous studies of bulk U6Fe provide evidence that the material may undergo a change or possible phase transition at around 110 K, while X-rays showed a CDW that appeared below 10 K. The interplay between CDW order and superconductivity is highly topical, both in the context of heavy fermions but also for high-temperature superconductivity. For U6Fe a CDW may promote the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, an unusual state in which the superconducting order parameter is modulated in real space. Previous neutron measurements showed the presence of disallowed nuclear Bragg peaks, suggesting the previously-reported crystal structure may be incomplete. We propose to measure the crystal strcutre of U6Fe at various temperatures to determine the nature of the crystal structure and how it may be affected by the phase transitions at 110K and 10K.

Principal Investigator: Dr Travis Williams
Experimenter: Dr Callum Stevens
Experimenter: Professor Andrew Huxley
Local Contact: Dr Matthias Gutmann

DOI: 10.5286/ISIS.E.RB2600001

ISIS Experiment Number: RB2600001

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 Travis Williams et al; (2026): Single crystal neutron diffraction determination of U6Fe Structure, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2600001

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