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Rare ferrimagnet states in a phase competing antiferromagnet.

From new neutron powder diffraction experiments on the chiral cubic (P213) magnet manganese germanide (MnGe), we analyze all of the possible crystal symmetry-allowed magnetic superstructures that are determined successfully from the data. The incommensurate propagation vectors k of the magnetic structure are found to be aligned with the [100] cubic axes, and correspond to a magnetic periodicity of about 30 Å at 1.8 K. Several maximal crystallographic symmetry magnetic structures are found to fit the data equally well and are presented. These include topologically nontrivial magnetic hedgehog and “skyrmion” structures in multi-k cubic or orthorhombic 3+3 and orthorhombic 3+2 dimensional magnetic superspace groups respectively, with either potentially responsible for topological Hall effect. The presence of orthorhombic distortions in the space group P212121 caused by the transition to the magnetically ordered state does not favor the cubic magnetic hedgehog structure, and leave both orthorhombic hedgehog and skyrmion models as equal candidates for the magnetic structures. We also report on a combined mechanochemical and solid-state chemical route to synthesize MnGe at ambient pressures and moderate temperatures, and compare with samples obtained by the traditional high pressure synthesis.

From light-years to nanometers: by repurposing an algorithm originally developed for the investigation of oscillatory dynamics in astronomical objects, scientists have been able to image non-locked dynamical processes at the nanosecond and nanometer scale.

We present magnetization and neutron powder diffraction studies in the temperature range 2K to 300K for oxygen stoichiometric R_1/3Sr_2/3FeO (R = Pr and Nd). From full symmetry analysis, we proposed two magnetic models by a combined application of irreducible representations and magnetic space groups. Both models fit equally well the neutron powder diffraction data.

Dr. Manuel Guizar-Sicairos, currently Senior Scientist at PSI, was appointed as Associate Professor of Physics in EPF Lausanne and head of the Computational X-ray Imaging group in PSI.

X-ray photoelectron spectroscopy probes the chemical environment in a molecule at a specific atomic site. Now the concept is extended with a site selective trigger to follow chemical bond changes as they occur on the femtosecond time scale.

The increasing risk of extended electricity supply disruptions and severe electricity price fluctuations  strongly motivate an evaluation of electricity supply resilience. In this direction, this research proposes a multicriteria decision support framework to assess resilience at a country level, based on three major dimensions: Resist, Restabilize and Recover. In total, 35 European countries are ranked according to their performance on 17 indicators, through a synergy of MCDA methods, techniques and communication protocols. The assessment framework has been extended to incorporate the Choquet Integral method, in order to accommodate potentially interacting pairs of criteria and negate their arbitrary effects on the final evaluation results. The analysis incorporates country data from credible international databases, as well as the preference information of a European energy expert. The results are envisaged to support energy policymakers in Europe and provide guidelines and areas for improvement at a country level.

GdSb_0.46Te_1.48, a nonsymmorphic Dirac semimetal with Dirac nodes at the Fermi level, has a rich magnetic phase diagram with one of the phases predicted to be an antiferromagnetic skyrmion state. In the current work, we investigate GdSb_0.71Te_1.22 through bulk magnetization measurements, single-crystal, and powder synchrotron X-ray diffraction, as well as single-crystal hot-neutron diffraction. We resolve a weak orthorhombic distortion with respect to the tetragonal structure and charge density wave (CDW) satellites due to incommensurate modulations of the crystal structure. At 2 K the magnetic structure is modulated with two propagation vectors, k_I = (0.45 0 0.45) and k_II = (0.4 0 0), with all their arms visible. While k_I persists up to the transition to the paramagnetic state at T_N = 11.9 K, k_II disappears above an intermediate magnetic transition at T₁ = 5 K. Whereas magnetic field applied along the c-axis has only a weak effect on the intensity of antiferromagnetic reflections, it is effective in inducing an additional ferromagnetic component on Gd atoms. We refine possible magnetic structures of GdSb_0.71Te_1.22 and discuss the possibility of hosting magnetic textures with non-trivial 3D+ 2 topologies in the GdSb_1−xTe_1+x series.

High-speed in situ X-ray diffraction is used to measure temperature profiles and cooling rates during 3D printing of a a Ti-6Al-4V single-track wall.

PSI has a unique (worldwide) environment for the investigation of highly radioactive / toxic materials:

> Materials (different fuel types, very high burn-up, different cladding materials, materials activated in SINQ).

> The hot lab with advanced tools for microsample analysis and preparation.

> The large-scale equipment for advanced material analysis.

This unique combination at PSI allows us to meet the needs of our industrial partners to improve plant safety / efficiency, up to fundamental research.

The quantitative distribution of fission products over the cross-section of a pellet with a shielded electron probe microanalyzer (EPMA) used for verification analysis of the material behavior to validate the model. In this context, Xe behavior during transients/failure (LOCA, RIA) is an important safety parameter that can’t be measured with the EPMA at the periphery. Microstructural EBSD investigations on a microsample extend the information horizon, which is deepened at the microXAS beamline by detailed X-ray analyses.

A consortium led by Dr. Giovanni Pizzi, Group leader of the “Materials Software and Data” group in the Laboratory for Materials Simulations, has won funding of almost CHF1.3 million for a three-year project dubbed PREMISE: “Open and reproducible materials science research.”  

The coupling of spin, charge and lattice degrees of freedom results in the emergence of novel states of matter across many classes of strongly correlated electron materials. A model example is unconventional superconductivity, which is widely believed to arise from the coupling of electrons via spin excitations. In cuprate high-temperature superconductors, the interplay of charge and spin degrees of freedom is also reflected in a zoo of charge and spin- density wave orders that are intertwined with superconductivity ...

When cycloalkanes are enclosed in a nanometer-sized pore, they adapt their shape - similar to the induced fit concept described in #biochemistry. The molecules do not all behave in the same way and surprisingly start to move when there is a lack of space at 5K.

Pressure, together with temperature, electric, and magnetic fields, alters the system and allows for the investigation of the fundamental prop- erties of matter. Under applied pressure, the interatomic distances shrink, which modifies the interactions between atoms and may lead to the appearance of new (sometimes exotic) physical properties, such as pressure-induced phase transitions; quantum critical points; new structural, magnetic, and/or superconducting states; and changes of the temperature evolution and symmetry of the order parameters...

Operando X-ray absorption spectroscopy revealed a linear correlation between the amount of oxidic Fe²⁺ and the ambient temperature activity of Pt−FeO_x preferential carbon monoxide oxidation catalysts. The hydrogen prereduction temperature and pressure determines the amount of active Fe²⁺ sites for alumina- and silica-supported Pt−Fe catalysts. Catalyst deactivation is linked with the oxidation of these sites.

Researchers from the Max Planck Institute for Biological Intelligence, Google Inc. and the Paul Scherrer Institute published a new method and data resource that makes connectomic analyses of the entire larval zebrafish brain possible.

Data science (DS) and artificial intelligence (AI) methods opens up an immense range of new opportunities and challenges in the context of continuously enhancing the complex methodologies used as basis for nuclear safety assessments. To this aim, following discussions in the ETSON Technical Board on Reactor Safety, the PSI laboratory for reactor physics and thermal-hydraulics organized on October 20-21, 2022, an international workshop to review and discuss DS/AI within ETSON, the network of European research and expert organizations providing scientific support to national nuclear authorities. With close to 40 participants, the workshop, organized as a hybrid meeting, allowed to put in evidence that similarly as at PSI, a wide and growing range of developments with integration of DS/AI methods are currently taking place in order to complement and/or inform nuclear safety analysis methodologies.  

Light Water Reactors (LWRs) such as the ones operating in Switzerland work at relatively high temperatures and pressures. As a consequence, thermal-hydraulics experiments investigating relevant LWRs phenomena at prototypical conditions require test sections with relatively thick steel walls. This poses significant challenges for the implementation of suitable instrumentation to capture phenomena of interest, such as the flow regimes during transition from liquid to steam. The characterization of flow regimes in the presence of boiling is rather complex, and their better understanding would allow to develop mathematical modeling tools that can be used to optimize equipment and better assess safety margins. To perform in-situ measurements of the boiling process under high-pressure conditions, the team of authors from PSI, ETH, and the University of Michigan has developed a new high-fidelity and high-speed imaging system based on x-ray radiography, which provides high-resolution details on the boiling process while being non-intrusive. Since the instrumentation is located outside of the test section, it has also the advantage that can be easily moved to take measurements in different region of the test sections. 

To celebrate contributions of highly influential early and mid-career researchers in energy research, the journal Energy & Fuels established an annual recognition of Energy and Fuels Rising Stars.

Dr. Manuel Guizar-Sicairos was elected as a 2022 SPIE Fellow Member for his contributions to coherent lensless imaging, including ptychography and X-ray nano-tomography. The distinction was awarded in the SPIE’s Optics & Photonics conference in San Diego, California.

Spinons are well-known as the elementary excitations of one-dimensional antiferromagnetic chains, but means to realize spinons in higher dimensions is the subject of intense research. Here, we use resonant x-ray scattering to study the layered trimer iridate Ba₄Ir₃O₁₀, which shows no magnetic order down to 0.2 K. An emergent one-dimensional spinon continuum is observed that can be well-described by XXZ spin-1/2 chains with magnetic exchange of ∼55 meV and a small Ising-like anisotropy. With 2% isovalent Sr doping ...

Many complex metals exhibit collective states in which electrons appear to collaborate to generate novel and frequently functional behavior. These states develop when metals are cooled down to remove the effects of thermal fluctuations, enabling collective states in which electrons move coherently through the material. These collective electronic states are of tremendous importance because they are the foundation for many quantum states of interest such as unconventional superconductivity, frustrated magnetism, hidden order, as well as topologically non-trivial and electronic-nematic states.

Kagome materials often host exotic quantum phases, including spin liquids, Chern gap, charge density wave, and superconductivity. Existing scanning microscopy studies of the kagome charge order have been limited to nonkagome surface layers. Here, we tunnel into the kagome lattice of FeGe to uncover features of the charge order. Our spectroscopic imaging identifies a 2 × 2 charge order in the magnetic kagome lattice, resembling that discovered in kagome superconductors. Spin mapping across steps of unit cell height demonstrates the existence of spin-polarized electrons with an antiferromagnetic stacking order.

The first magnet series consisting of 112 quadrupole electromagnets for SLS2.0 were measured to high precision using a special home-made rotating coils measurement system. This is an important step forward for the realization of SLS2.0, the upgrade of the Swiss Light Source (SLS) at PSI, and a milestone for the members of the Magnet Section in GFA.

Dr. Francesca Borgna, former Marie Curie Fellow at the Center for Radiopharmaceutical Sciences awarded by the Institute of Pharmaceutical Sciences in 2022 and gave the IPW Young Scientist lecture entitled: "Combination of Terbium-161 with Somatostatin Receptor Antagonists: a Potential Paradigm Shift for the Treatment of Neuroendocrine Neoplasm.

Magnetic skyrmions stabilized in synthetic antiferromagnets hold promise as nanoscale information carriers in novel non-volatile magnetic memory designs. In this work, scientists in a worldwide collaborative effort have demonstrated the electrically-induced nucleation of magnetic skyrmions in synthetic antiferromagnets, which is a vital stepping stone towards the applicability of these magnetic textures in devices.

Scientists have demonstrated, through magnetic X-ray microscopy, that magnetic skyrmions stabilized in ferrimagnetic heterostructures can be displaced by electrical currents at high velocities, and exhibit low deflection angles, proving that ferrimagnetic skyrmions are good candidates for fast skyrmionic devices.

In situ alloying is an effective method to engineer microstructures of additively manufactured Ti6Al4V3Fe alloys. 

We are happy to announce that Alex has been awarded the 2022 Nicholas Kurti Science prize. The prize recognises his work on non-linear effects in Josephson junctions for quantum information processing.

The kagome metals of the family AV₃Sb₅, featuring a unique structural motif, harbor an array of intriguing phenomena such as chiral charge order and superconductivity. CsV₃Sb₅ is of particular interest because it displays a double superconducting dome in the region of the temperature-pressure phase diagram where charge order is still present. However, the microscopic origin of such an unusual behavior remains an unsolved issue. Here, to address it, we combine high-pressure, low-temperature muon spin relaxation/rotation with first-principles calculations. We observe ....

We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr_14−xCa_xCu₂₄O₄₁ (SCCO) using Cu L₃-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without (x = 0) Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2 T) excitations (x = 0) to weakly- dispersive gapped modes at an energy of 280 meV (x = 12.2)...

A new incrementally extendable thermodynamic model, CASH+, was developed, aimed at accurately describing equilibrium composition, solubility, and elemental uptake of C-A-S-H gel-like phases at varying chemical conditions in cement systems. Cement is widely used as matrix and backfill for low and intermediate level waste. Calcium-Aluminum-Silicate Hydrates (C-A-S-H) are the most important binding phases in cement. They are also responsible for the initial entrapment of radionuclides via sorption or solid solution formation mechanisms. Therefore, the thermodynamic modelling of C-A-S-H stability, solubility and interaction with radionuclides in cement porewater is crucial for understanding hydration, blending, degradation of cement-based materials and for the performance assessment of cementitious repositories.

We report on the first example of quantum coherence between the spins of muons and quadrupolar nuclei. We reveal that these entangled states are highly sensitive to a local charge environment and thus, can be deployed as a functional quantum sensor of that environment. The quantum coherence effect was observed in vanadium intermetallic compounds which adopt the A15 crystal structure, and whose members include all technologically pertinent superconductors. Furthermore ...

Rahel Wallimann, PhD student in the “Nuclide Chemistry Group”, received the first prize (AKB Foundation) of the SAPhW Poster Award at the Swiss Pharma Science Day 2022.

We report an excellent realization of the highly nonclassical incommensurate spin-density wave (SDW) state in the quantum frustrated antiferromagnetic insulator Cs₂CoBr₄. In contrast to the well-known Ising spin chain case, here the SDW is stabilized by virtue of competing planar in-chain anisotropies and frustrated interchain exchange.

The fuel used for nuclear energy production is normally enclosed in zirconium-based cladding tubes that constitute the first barrier between the radioactive material and the environment. In water-moderated reactors, cladding tubes tend to corrode, generating hydrogen as side product. The study of the hydrogen embrittlement in zirconium alloys is of high relevance for the industry.

Depending on temperature, local hydrogen concentration, and local stress conditions, different hydrogen-induced embrittlement mechanisms can be active in the cladding material: in certain conditions hydrogen in solid solution might cause material softening through a mechanism known as hydrogen enhanced localized plasticity (HELP).

With the goal of determining the conditions necessary to activate the HELP effect in zirconium alloys, samples have been evaluated by different micro-mechanical and macro-mechanical techniques. Results highlight the importance of the interplay between solid solution hydrogen and hydrides on the hardness and yield point of the tested materials.

The van-der-Waals material CrSBr stands out as a promising two-dimensional magnet. Here, we report on its detailed magnetic and structural character- istics. We evidence that it undergoes a transition to an A-type anti- ferromagnetic state below T_N ≈ 140 K with a pronounced two-dimensional character, preceded by ferromagnetic correlations within the monolayers. Furthermore, we unravel the low-temperature hidden-order within the long- range magnetically-ordered state. We find that it is associated to a slowing down of the magnetic fluctuations, accompanied by a continuous reorienta- tion of the internal field.

How are the first olefins formed in the early stages of the methanol-to-olefins process? Detection of two reactive ketene species solves this long-standing puzzle.

The conversion of solar light into hydrogen by photoelectrochemical water splitting is one of the potential strategies that can allow the development of a carbon-neutral energy cycle. Oxynitride semiconductors are promising materials for this application, although important limitations must still to be addressed. One of the most important issues is physicochemical degradation of the semiconductor, at the interface with water, where the electrochemical reactions occur. In this regard, thin films, with well-defined and atomically flat surfaces, are invaluable tools for characterizing material properties and degradation mechanisms, while identifying strategies to mitigate detrimental effects. Thin oxynitride films may allow the use of complementary characterizations, not applicable to conventional powder samples. In particular, the study of the solid–liquid interface can benefit enormously from the use of thin films for synchrotron-based surface-sensitive X-Ray scattering methods and neutron reflectometry. These investigation approaches promise to speed up the design and discovery of new materials for the production of solar fuels, while paving the way for similar applications in other research fields. This work aims at reviewing the literature contributions on oxynitride thin films for solar water splitting summarizing what is learnt so far and suggesting experimental strategies to unveil what is still not clear.

We present a novel monitoring strategy for 3D print processes that consists of developing and training a hybrid machine learning model that can classify regimes across different time scales based on heterogeneous sensing data.