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Zerva et al., 2025

Surface diffusion of cationic species has frequently been postulated to explain the results of diffusion studies in compacted clay minerals and clay rocks. However, the underlying mechanism of this process is not well understood, and the factors controlling the diffusive flux are not yet satisfactorily quantified. In this study, the role of ion-specific molecular interactions in the electric double layer formed at the clay mineral-fluid interface is investigated...

John Provis is studying concrete and the complex interplay between its many components. The aim is to develop a better understanding of this building material and make it more sustainable. © Paul Scherrer Institute PSI/Mahir Dzambegovic

Prasianakis, N. I., et al.

Thanks to the recent progress in numerical methods and computer technology, the application fields of artificial intelligence (AI) and machine learning methods (ML) are growing at a very fast pace. The field of geochemistry for nuclear waste management has recently started using ML for the acceleration of numerical simulations of reactive transport processes, for the improvement of multiscale and multiphysics couplings efficiency, and for uncertainty quantification and sensitivity analysis......

The observation of superconductivity in La₃Ni₂O_7–δ under pressure, following the suppression of a high-temperature density wave state, has attracted considerable attention. The nature of this density wave order was not clearly identified. Here we probe the magnetic response of the zero-pressure phase of La₃Ni₂O_7–δ as hydrostatic pressure is applied, and find that the apparent single density wave transition at zero applied pressure splits into two. The comparison of our muon-spin rotation ...

Encoding information in antiferromagnetic (AFM) domains is a promising solution for the ever growing demand in magnetic storage capacity. The absence of a macroscopic magnetization avoids crosstalk between different domain states, enabling ultrahigh density spintronics while being detrimental to the domain detection and manipulation. Disentangling these merits and disadvantages seemed so far unattainable. We report evidence ...

Spin moiré superlattices (SMSs) formed by interfacing conventional electronic states with a multi-q magnetic lattice have been proposed as a magnetic analog of crystallographic moiré systems. The electron-minibands created in an SMS are expected to be enriched by the vector-field nature of the magnetic interaction and offer new types of moiré tunability, topological protection, and Berry curvature effects. However, most spin-vortex-hosting systems discovered to date have carrier mean free paths l_mfp significantly shorter than their spin-moiré lattice constant a_spin, inhibiting mini-band-formation. Furthermore ...

Skyrmions are particlelike vortices of magnetization with nontrivial topology, which are usually stabilized by Dzyaloshinskii-Moriya interactions (DMI) in noncentrosymmetric bulk materials. Exceptions are centrosymmetric Gd- and Eu-based skyrmion-lattice (SL) hosts with zero DMI, where both the SL stabilization mechanisms and magnetic ground states remain controversial. We address these here by investigating both the static and dynamical spin properties  ...

Energy-efficient, safe, and reliable Li-ion batteries (LIBs) are required for a wide range of applications. The introduction of ultra-thick graphite anodes, desired for high energy densities, meets limitations in internal electrode transport properties, leading to detrimental consequences. Yet, there is a lack of experimental tools capable of providing a complete view of local processes. Here, a multi-modal operando measurement approach is introduced, enabling quantitative spatio-temporal observations of Li concentrations and intercalation phases in ultra-thick graphite electrodes.
Neutron imaging and diffraction concurrently provide ...

The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe₂ is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry Y and T points and disperse along the crystallographic b-axis. In applied magnetic fields ...

Methods to prepare and characterize neutron helical waves carrying orbital angular momentum (OAM) were recently demonstrated at small-angle neutron scattering (SANS) facilities. These methods enable access to the neutron orbital degree of freedom which provides new avenues of exploration in fundamental science experiments as well as in material characterization applications. 

However, ....

Antiferromagnets with exotic spin textures promise low-power spintronic devices with extremely high operating frequencies and resistance to external perturbations. In particular, the combination of highly tunable correlated electron physics, as in complex oxides, with metallicity and antiferromagnetism is desirable but exceedingly rare. LaNiO₃, the lone example of a perovskite nickelate which is metallic across all temperatures, has long been a promising candidate, but the antiferromagnetic metallic state has remained elusive. We demonstrate the emergence  ...

The PSI Laboratory for Reactor Physics and Thermal-Hydraulics (LRT) conducts computational and experimental research with focus on the safety of nuclear reactors and systems. In recent years, it established the EPSILON program to coordinate and consolidate its research activities on nuclear space applications. Among other things, developments were initiated towards an open-source European platform for high-fidelity simulations and experiments dedicated to space nuclear reactors. Referred to as the open^SPACE platform, its underlying concepts are a) to include not only solvers but also reference simulation models as well as experimental validation data; b) to make all of these available to the broader and combined nuclear- and space communities for usage and/or further developments. Through this, the goal is thus not only to facilitate collaborative research in this area but also to enable effective support to the European Space Agency for thorough design, safety and performance evaluations of nuclear reactor systems for in-space propulsion and/or surface power. A first development phase focused on nuclear electric propulsion was proposed and retained among the two projects selected in 2023 by the Swiss National Science Foundation (SNSF) for its MARVIS call (Multidisciplinary Advanced Research Ventures in Space) and funded by the Swiss Secretariat for Research and Innovation (SERI). This project, to be conducted via four inter-connected PhD theses, was launched in October 2024 and this marks thus a key milestone for the propulsion of PSI nuclear research towards space.

We experimentally study the evolution of the magnetic moment 𝑚 and exchange interaction 𝐽 as a function of hydrostatic pressure in the zero-field helimagnetic phase of the strongly correlated electron system MnSi. The suppression of magnetic order at ≈1.5  GPa is shown to arise from the 𝐽 collapse and not from a quantum fluctuations induced reduction of 𝑚. Our work provides benchmarks ...

Additive manufacturing (AM) or “3D printing” of metals, which builds structure layer by layer, has revolutionized the production of intricate 3D designs. Among its techniques, laser powder bed fusion (PBF-LB) excels in creating metallic parts with intricate designs and high precision. This process can combine different metals into innovative multi-material components with tailored properties, with regards to e.g., strength and thermal conductivity, surpassing the capabilities of single-material designs. However, ....

Magnetic, thermodynamic, neutron diffraction and inelastic neutron scattering are used to study spin correlations in the easy-axis XXZ triangular lattice magnet K₂Co(SeO₃)₂. Despite the presence of quasi-2D “supersolid” magnetic order, the low-energy excitation spectrum contains no sharp modes and is instead a broad and structured multiparticle continuum. Applying a weak magnetic field ...

Topologically nontrivial magnetic structures such as skyrmion lattices are well known in materials lacking lattice inversion symmetry, where antisymmetric exchange interactions are allowed. Only recently, topological multi-q magnetic textures that spontaneously break the chiral symmetry, for example, three-dimensional hedgehog lattices, were discovered in centrosymmetric compounds, where they are instead driven by frustrated interactions. Here we show that ...

Researchers from an international collaboration between the United States of America and Switzerland have performed three-dimensional magnetic imaging of a magnetic skyrmion using soft X-ray laminography. This allowed for the investigation, in three dimensions, of the topological profile of the magnetic skyrmions.

Even as a student, Athanasios Mokos was excited by the dynamics of fluids. Today at the Paul Scherrer Institute PSI, he models complex processes such as the formation of deposits on reactor fuel rods.

Researchers at the Paul Scherrer Institute PSI have shown that artificial neural networks have the potential to determine very precisely the characteristics of rock layers, like their mineralogical composition, solely on the basis of drill core images. This could speed up future geological investigation efforts while simultaneously optimising costs.

Quantum critical points (QCPs), zero-temperature phase transitions, are win- dows to fundamental quantum-mechanical phenomena associated with universal behaviour. Magnetic QCPs have been extensively investigated in the vicinity of antiferromagnetic order. However, QCPs are rare in metallic ferromagnets due to the coupling of the order parameter to electronic soft modes. Recently, antisymmetric spin-orbit coupling in noncentrosymmetric systems was suggested to protect ferromagnetic QCPs. Nonetheless, multiple centrosymmetric materials ...

The extraordinary properties of the Kitaev model have motivated an intense search for new physics in materials that combine geometrical and bond frustration. In this Letter, we employ inelastic neutron scattering, spin wave theory, and exact diagonalization to study the spin dynamics in the perfect triangular-lattice antiferromagnet (TLAF) CsCeSe₂. This material orders into a stripe phase, which is demonstrated to arise as a consequence of the off-diagonal bond-dependent terms in the spin Hamiltonian ...