Improving the study of atoms under pressure

Along with temperature and the magnetic field, pressure is an important thermodynamic parameter

in physics. Pressure decreases interatomic distances, which modifies interactions between atoms and leads to the appearance of new, sometimes exotic, physical properties. Pressure experiments are used to establish phase diagrams, study phase transitions, and identify critical points. Rustem Khasanov describes the requirements needed to study the atomic behavior of materials under high pressure by applying the muon spin rotation/relaxation technique.

The review shows how an established technique can be applied to more precisely study materials under extreme pressure conditions. Khasanov describes instrumentation located at the Paul Scherrer Institute in Switzerland and how it can be used to perform muon-spin rotation/relaxation experiments under hydrostatic pressure. He then demonstrates how such experiments can help researchers understand the effect of high pressure on properties like magnetism, superfluidity, symmetry breaking, and superconductivity.

“Muon-spin rotation/relaxation (μSR) experiments provide insights into how it interacts with its local environment, and conducting these experiments under pressure allows us to obtain unique information on the static and dynamic properties of the material of interest,” Khasanov said. “This enables μSR to become a powerful tool to investigate material properties.”

The instruments can be improved in several ways, such as using stronger materials for the cells within the instruments to sustain higher pressures and adding a system that would enable scientists to change the pressure directly at the point of interaction.

Source: “Perspective on muon-spin rotation/relaxation under hydrostatic pressure,” by Rustem Khasanov, Journal of Applied Physics (2022). The article can be accessed at https://doi.org/10.1063/5.0119840 .