Here you find current and previous news from the NUM division. For scientific highlights, please have a look here.
In the search for New Physics at the Intensity Frontier: a first result from the MEG II experiment
In a special seminar at the Paul Scherrer Institut (PSI) in Switzerland, the MEG II collaboration presented on October 20th its first results, based on data collected in 2021. The results are reported on a paper published on arXiv and submitted to the European Journal of Physics C.
Japanese – Swiss BRIDGE Workshop at PSI
BRIDGE stands for Bridging Research Innovations in Diverse muon and neutron science by GEneral collaboration between Japan and Switzerland. After a first remote edition of this new workshop series in 2022, an in-person BRIDGE workshop took place at PSI, October 18-20, 2023.
Integrative solution structure of PTBP1-IRES complex reveals strong compaction and ordering with residual conformational flexibility
RNA-binding proteins (RBPs) are crucial regulators of gene expression, often composed of defined domains interspersed with flexible, intrinsically disordered regions. Determining the structure of ribonucleoprotein (RNP) complexes involving such RBPs necessitates integrative structural modeling due to their lack of a single stable state. In this study, we integrate magnetic resonance, mass spectrometry, and small-angle scattering data to determine the solution structure of ...
Electrically programmable magnetic coupling in an Ising network exploiting solid-state ionic gating
Two-dimensional arrays of magnetically coupled nanomagnets provide a mesoscopic platform for exploring collective phenomena as well as realizing a broad range of spintronic devices. In particular, the magnetic coupling plays a critical role in determining the nature of the cooperative behavior and providing new functionalities in nanomagnet-based devices. Here, we create coupled Ising-like nanomagnets ...
Efficient magnetic switching in a correlated spin glass
The interplay between spin-orbit interaction and magnetic order is one of the most active research fields in condensed matter physics and drives the search for materials with novel, and tunable, magnetic and spin properties. Here we report on a variety of unique and unexpected observations in thin multiferroic Ge1−xMnxTe films.
Direct observation of topological magnon polarons in a multiferroic material
Magnon polarons are novel elementary excitations possessing hybrid magnonic and phononic signatures, and are responsible for many exotic spintronic and magnonic phenomena. Despite long-term sustained experimental efforts in chasing for magnon polarons, direct spectroscopic evidence of their existence is hardly observed. Here, we report the direct observation of magnon polarons using neutron spectroscopy on a multiferroic Fe2Mo3O8 possessing strong magnon-phonon coupling.
Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe2
Fifty years after Anderson’s resonating valence-bond proposal, the spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) remains the ultimate platform to explore highly entangled quantum spin states in proximity to magnetic order. Yb-based delafossites are ideal candidate TLHAF materials, which allow experimental access to the full range of applied in-plane magnetic fields. We perform a systematic neutron scattering study of CsYbSe2, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling.
PSI medal winners at SwissSkills Championships 2023
At the recent SwissSkills Championships 2023 for apprentices in Sindex/BE Melvin Deubelbeiss and Andrin Kästli from the electronics apprenticeship group in NUM/LTP have won two medals: Andrin became third, won a bronze medal and Melvin even won the championship and was honored by the gold medal.
Field-tuned quantum renormalization of spin dynamics in the honeycomb lattice Heisenberg antiferromagnet YbCl3
The basis for our understanding of quantum magnetism has been the study of elegantly simple model systems. However, even for the antiferromagnetic honeycomb lattice with isotropic spin interactions – one of the simplest model systems – a detailed understanding of quantum effects is still lacking. Here, using inelastic neutron scattering measurements of the honeycomb lattice material YbCl3, we elucidate how quantum effects renormalize ...
Swiss precision optics in Sweden
PSI has finalized the precision Selene neutron optics for the ESTIA instrument. The complex state-of-the-art guide was installed at the European Spallation Source as a Swiss in-kind delivery.
Spin-orbit driven superconducting proximity effects in Pt/Nb thin films
Manipulating the spin state of thin layers of superconducting material is a promising route to generate dissipationless spin currents in spintronic devices. Approaches typically focus on using thin ferromagnetic elements to perturb the spin state of the superconducting condensate to create spin-triplet correlations. We have investigated simple structures that generate spin-triplet correlations without using ferromagnetic elements.
Unconventional charge order and superconductivity in kagome-lattice systems as seen by muon-spin rotation
Kagome lattices are intriguing and rich platforms for studying the intertwining of topology, electron correlation, and magnetism. These materials have been subject to tremendous experimental and theoretical studies not only due to their exciting physical properties but also as systems that may solve critical technological problems. We will review recent experimental progress on superconductivity and magnetic fingerprints of charge order in several kagome-lattice systems from the local-magnetic probe point of view by utilizing muon-spin rotation under extreme conditions, i.e., hydrostatic pressure, ultra low temperature and high magnetic field.
Strong phonon softening and avoided crossing in aliovalence-doped heavy-band thermoelectrics
Aliovalent doping is a way to optimize the electrical properties of semiconductors, but its impact on the phonon structure and propagation is seldom considered properly. Here we show that aliovalent doping can be much more effective in reducing the lattice thermal conductivity of thermoelectric semiconductors than the commonly employed isoelectronic alloying strategy. We demonstrate ...
Direct observation of exchange anisotropy in the helimagnetic insulator Cu2OSeO3
The helical magnetic structures of cubic chiral systems are well explained by the competition among Heisen- berg exchange, Dzyaloshinskii-Moriya interaction, cubic anisotropy, and anisotropic exchange interaction (AEI). Recently, the role of the latter has been argued theoretically to be crucial for the low-temperature phase diagram of the cubic chiral magnet Cu2OSeO3, which features tilted conical and disordered skyrmion states for a specific orientation of the applied magnetic field (μ0H⃗ ∥ [001]). In this study ...
Une pointe de flèche de l’âge du bronze en fer météorite
Les scientifiques du PSI s’aident des muons pour déterminer la provenance d’une pointe de flèche.
Emergent Magnetism with Continuous Control in the Ultrahigh-Conductivity Layered Oxide PdCoO2
The current challenge to realizing continuously tunable magnetism lies in our inability to systematically change properties, such as valence, spin, and orbital degrees of freedom, as well as crystallographic geometry. Here, we demonstrate that ferromagnetism can be externally turned on with the application of low-energy helium implantation and can be subsequently erased and returned to the pristine state via annealing.
L’énigme des microgels a été élucidée
Des chercheurs du PSI et de l’Université de Barcelone ont réussi à expliquer de manière expérimentale l’étrange rétraction des microgels.
Coupling of magnetic phases at nickelate interfaces
In this paper we present a model system built out of artificially layered materials, allowing us to understand the interrelation of magnetic phases with the metallic-insulating phase at long length scales, and enabling new strategies for the design and control of materials in devices. The artificial model system consists of superlattices made of SmNiO3 and NdNiO3 layers, – two members of the fascinating rare earth nickelate family, having different metal-to-insulator and magnetic transition temperatures. By combining two complementary techniques ....
Resonant Elastic X-Ray Scattering of Antiferromagnetic Superstructures in EuPtSi3
We report resonant elastic x-ray scattering of long-range magnetic order in EuPtSi3, combining different scattering geometries with full linear polarization analysis to unambiguously identify magnetic scattering contributions. At low temperatures, EuPtSi3 stabilizes type A antiferromagnetism featuring various long- wavelength modulations. For magnetic fields applied in the hard magnetic basal plane, well-defined regimes of cycloidal, conical, and fanlike superstructures may be distinguished that encompass a pocket of commensurate type A order without superstructure.
Defect Profiling of Oxide-Semiconductor Interfaces Using Low-Energy Muons
Muon spin rotation with low-energy muons (LE-μSR) is a powerful nuclear method where electrical and magnetic properties of surface-near regions and thin films can be studied on a length scale of ≈200 nm. This study shows the potential of utilizing low-energy muons for a depth-resolved characterization of oxide-semiconductor interfaces, i.e., for silicon (Si) and silicon carbide (4H-SiC). The performance of semiconductor devices relies heavily on the quality of the oxide-semiconductor interface; thus, investigation of defects present in this region is crucial to improve the technology.
Shea Distinguished Member Award of IEEE NPSS to Stefan Ritt
The Nuclear & Plasma Sciences Society of IEEE acknowledges the outstanding contributions of Dr. Stefan Ritt in terms of technological developments and services to the NPSS community with the 2023 Richard F. Shea Distinguished Member Award.
Tuning magnetoelectricity in a mixed-anisotropy antiferromagnet
Control of magnetization and electric polarization is attractive in relation to tailoring materials for data storage and devices such as sensors or antennae. In magnetoelectric materials, these degrees of freedom are closely coupled, allowing polarization to be controlled by a magnetic field, and magnetization by an electric field, but the magnitude of the effect remains a challenge in the case of single-phase magnetoelectrics for applications.
Marino Missiroli elected Trigger Coordinator of the CMS experiment at CERN
Marino Missiroli, a postdoctoral researcher in the High-Energy Particle Physics group of the Laboratory for Particle Physics (LTP) in NUM, will join the management team of the CMS experiment at CERN as Trigger Co-Coordinator in September 2023.
Laura Heyderman elected Royal Society Fellow
Laura’s nomination recognises almost 30 years of research into magnetic materials and magnetism on the nanoscale.
A deep look into hydration of cement
Researchers led by the University of Málaga show the Portland cement early age hydration with microscopic detail and high contrast between the components. This knowledge may contribute to more environmentally friendly manufacturing processes.
Nodeless electron pairing in CsV3Sb5-derived kagome superconductors
The newly discovered kagome superconductors represent a promising platform for investigating the interplay between band topology, electronic order and lattice geometry. Despite extensive research efforts on this system, the nature of the superconducting ground state remains elusive. In particular, consensus on the electron pairing symmetry has not been achieved so far, in part owing to the lack of a momentum-resolved measurement of the superconducting gap structure. Here we report ...
Quantum disordered ground state in the triangular-lattice magnet NaRuO2
It has long been hoped that spin liquid states might be observed in materials that realize the triangular-lattice Hubbard model. However, weak spin–orbit coupling and other small perturbations often induce conventional spin freezing or magnetic ordering. Sufficiently strong spin–orbit coupling, however, can renormalize the electronic wavefunction and induce anisotropic exchange interactions that promote magnetic frustration.
Active learning-assisted neutron spectroscopy with log-Gaussian processes
Neutron scattering experiments at three-axes spectrometers (TAS) investigate magnetic and lattice excitations by measuring intensity distributions to understand the origins of materials properties. The high demand and limited availability of beam time for TAS experiments however raise the natural question whether we can improve their efficiency and make better use of the experimenter’s time.
Une mission sur Jupiter pour explorer les conditions favorables à la vie
Ganymède, Callisto et Europe sont trois lunes glacées de Jupiter et la destination de la mission de l’ESA, qui emporte à bord un détecteur high-tech du PSI.
Amyloid-polysaccharide interfacial coacervates as therapeutic materials
Coacervation via liquid-liquid phase separation provides an excellent oppor- tunity to address the challenges of designing nanostructured biomaterials with multiple functionalities. Protein-polysaccharide coacervates, in particular, offer an appealing strategy to target biomaterial scaffolds, but these systems suffer from the low mechanical and chemical stabilities of protein-based condensates. Here we overcome these limitations by transforming native proteins into amyloid fibrils and demonstrate ...