Structural characterisation of emerging functional materials: when you need muons and neutrons from across Europe to build a full picture
10 Aug 2026 - Rosie de Laune
Researchers from Durham University and colleagues from Rutgers (The State University of New Jersey) and the University of Edinburgh have collaborated with teams from ISIS, the Institut Laue-Langevin (ILL) and the PSI Center for Neutron and Muon Sciences to carry out a full characterisation of the double perovskite Pb2MgReO6.
Emerging technologies require increasingly unusual functional materials. Therefore, understanding the origins of complex magnetic and electronic behaviour, and how these can be tuned, is crucial. Materials adopting the perovskite structure are an important research focus because they can accommodate a huge range of elements to give tailored physical properties.
In this study, published in the Journal of Materials Chemistry C, the researchers focussed on the perovskite Pb2MgReO6. In this material, the heavy Re6+ cation has the potential to adopt unusual magnetic states. The structural behaviour of this type of perovskite, and the resulting site symmetry of the magnetic cations, play a key role in determining the properties and magnetic ground state of the material.
To fully characterise the structure and magnetic behaviour, the group needed to use both neutrons and muons. They carried out neutron powder diffraction on WISH at ISIS and D2B at ILL before doing a series of muon-spin relaxation measurements at different field strengths using EMU, with some supporting measurements done on GPS at the Paul Scherrer Institute.
The synthesis of this material requires high pressure and temperature, and so only a small amount could be produced. However, the capabilities of both WISH and EMU meant the team were still able to carry out their neutron and muon experiments, even with a small 400 mg sample.
It was a privilege to collect fantastic neutron and muon data, and to work alongside the expert instrument scientists, to understand this complex material
Emma E. McCabe, Associate Professor in Physics, Durham University
Neutron diffraction enabled them to fully characterise the crystal structure of the material, which showed a shift of the Pb cations from the high symmetry positions due to a second-order Jahn-Teller effect. This distortion strongly affected the other ion positions and symmetries to such a degree that the quadrupolar order seen in related compound is not observed.
They didn’t see any evidence of long-range magnetic order at low temperatures using neutrons, perhaps due to the small magnetic moment expected for this type of material. They therefore needed to use muons to investigate further.
Muons are sensitive to the local magnetism of a system and its dynamics. Their measurements at low temperature (<11.5 K) indicated the presence of long-range magnetic order. For temperatures between 11.5 and 30 K, their measurements suggest significant changes occur in the magnetic behaviour, indicative of short-range magnetic ordering.
“It was a privilege to collect fantastic neutron and muon data, and to work alongside the expert instrument scientists, to understand this complex material,” Emma E. McCabe, Associate Professor in Physics, Durham University
The full article can be found at DOI: 10.1039/d6tc01983h
Co-author, Tom Lancaster based at Durham University, is supported by EPSRC funding.
