Data Science

Artist concept of a 1D spin wave

A new spin in nano-electronics

In recent years, electronic data processing has been evolving in one direction only: The industry has downsized its components to the nanometer range. But this process is now reaching its physical limits. Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the Paul Scherrer Institut (PSI) are therefore exploring spin waves or so-called magnons – a promising alternative for transporting information in more compact microchips. Cooperating with international partners, they have successfully generated and controlled extremely short-wavelength spin waves. The physicists achieved this feat by harnessing a natural magnetic phenomenon, as they explain in the journal Nature Nanotechnology.

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Additive Manufacturing of High Entropy Alloys

Additive manufacturing of high-entropy alloys combines the mechanical properties of this novel family of alloys with the geometrical freedom and complexity required by modern designs. An approach to additive manufacturing of high-entropy alloys has been developed based on 3D extrusion of inks containing a blend of oxide nanopowders (Co3O4 + Cr2O3 + Fe2O3 + NiO), followed by co-reduction to metals, inter-diffusion and sintering to near-full density CoCrFeNi in H2. A complex phase evolution path is observed by in-situ X-ray diffraction in extruded filaments: the oxide phases undergo reduction and the resulting metals inter-diffuse, ultimately forming the desired fcc-CoCrFeNi alloy (see figure). Linked to this phase evolution is a complex micro-structural one, from loosely packed oxide particles to fully-annealed, metallic CoCrFeNi with 99.6 ± 0.1% relative density. CoCrFeNi micro-lattices are created with strut diameters as low as 100 μm and excellent mechanical properties at ambient and cryogenic temperatures.

Micro- and nano-calcifications as well as collagen, elastin and myofilament have been mapped using scanning SAXS and WAXS

Insights into a well-known disease in ageing populations: Abdominal and popliteal aneurysm

Abdominal aortic aneurysm, an enlargement of the abdominal aorta, may lead to rupture and thus acute health issues and death. Scanning X-ray imaging enabled new insights in the nano-structure of calcifications associated with abdonimal and popliteal aneurysm and allowed mapping the distribution of nano- and micro-calcifications as well as of collagen, elastin and myofilament as building blocks of connective tissue across samples from human donors.

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Meeting on Mu3e detector construction in Wengen

We spent four days in Wengen, Switzerland going over the details of the Mu3e detector and discussing the procedures for producing and integrating the sub-detectors. Safety, powering, cooling, electronics and readout were also among the topics.

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Teamevent Informatiker EFZ

Was erwartet uns im Adventureroom in Baden? Wir sind gespannt und stürzen uns auf ein unbekanntes Abenteuer.

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Teamevent Elektroniker EFZ

Ein Battle im Battlepark in Schwerzenbach und ein feines Essen im Restaurant Picone bildete der Rahmen des Teamevents der Lernenden Elektroniker EFZ.

Dr. Margie Olbinado joins as Industrial Liaison Scientist

Dr. Margie Olbinado joins the X-ray Tomography group as scientist to take care of industrial tomographic imaging and business strategies for the growing TOMCAT industrial portfolio. Before joining PSI, Margie was a scientist at The European Synchrotron - ESRF in France. As industrial liaison, she will work in collaboration with the PSI Technology Transfer, ANAXAM and SLS TT AG. 

Figure 1. Layout depicting the experimental conditions at the Alvra experimental station. (b) Fresnel simulation of the Talbot carpet: intensity distribution of the experimental conditions for a 1D diamond phase grating with a 200 nm pitch and 2.985 keV photon energy. The inset (c) shows the detailed structure of the interference pattern in the vicinity of the sample where the pitch is 190 nm

Towards X-ray Transient Grating Spectroscopy at SwissFEL

The high brilliance of new X-ray sources such as X-ray Free Electron Laser opens the way to non-linear spectroscopies. These techniques can probe ultrafast matter dynamics that would otherwise be inaccessible. One of these techniques, Transient Grating, involves the creation of a transient excitation grating by crossing X-ray beams on the sample. Scientists at PSI have realized a demonstration of such crossing by using an innovative approach well suited for the hard X-ray regime.

Ion-Induced Formation of Nanocrystalline Cellulose Colloidal Glasses Containing Nematic Domains

Controlling the assembly of colloids in dispersion is a fundamental approach toward the production of functional materials. Nanocrystalline cellulose (NCC) is a charged nanoparticle whose colloidal interactions can be modulated from repulsive to attractive by increasing ionic strength.

Cryo-TEM investigation of a free-standing monolayer of a calixarene derivative. The TEM-Picture on the left shows the monolayer deposited on a lacey carbon support. The electron diffraction pattern on the left confirms the formation of a crystalline monolayer

Supramolecular architectures of molecularly thin yet robust free-standing layers

In a collaboration within the network of the Swiss Nanoscience Institute, the formation of free-standing molecular monolayers using self-assembly processes has been demonstrated. The results of the study have been published in the February 2019 issue of Science Advances.

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Accelerating small-angle scattering experiments on anisotropic samples using kernel density estimation

We propose a method to accelerate small-angle scattering experiments by exploiting spatial correlation in two-dimensional data. We applied kernel density estimation to the average of a hundred short scans and evaluated noise reduction effects of kernel density estimation (smoothing).

Das PSI hat am Diversity-Index Switzerland 2018 den 2. Rang erreicht!

Ziel des Diversity Index ist es, die Heterogenität der Belegschaften in Schweizer Institutionen und Unternehmen zu messen und aufzuzeigen, in welchen Bereichen Handlungsbedarf besteht. An der Erhebung 2018 haben 30 Unternehmen teilgenommen.

A quantum magnet with a topological twist

A quantum magnet with a topological twist

Theories predict that some electrons in the kagome materials have exotic, so-called topological behaviors and others behave somewhat like graphene, another material prized for its potential for new types of electronics. 

Photos of (a) the cast CeAlGe rod, and the floating-zone-grown crystals of (b) CeAlGe and (c) PrAlGe.

Bulk single-crystal growth of the theoretically predicted magnetic Weyl semimetals RAlGe (R = Pr, Ce)

We explore two methods for single-crystal growth of the theoretically proposed magnetic Weyl semimetals RAlGe (R = Pr, Ce), which prove that a floating-zone technique, being both crucible- and flux-free, is crucial to obtain perfectly stoichiometric RAlGe crystals. In contrast, the crystals grown by a flux-growth technique tend to be Al-rich. We further present both structural and elemental analyses, along with bulk magnetization and electrical resistivity data on the crystals prepared by the floating-zone technique. Both systems with the intended 1:1:1 stoichiometry crystallize in the anticipated polar I41md (No. 109) space group, although neither displays the theoretically expected ferromagnetic ground state.

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Neue Betriebsbewilligung

Am 21. Februar 2019 erteilte das Eidgenössische Departement für Umwelt, Verkehr, Energie und Kommunikation (UVEK) die neue Betriebsbewilligung für die Anlage PSI Hotlabor

Scheme of the XMCD mechanism and example spectrum.

New Method for Calculating Soft X-ray Magnetic Circular Dichroism Spectra

Scientists have demonstrated in a combined theoretical and experimental effort that the new ligand-field density functional theory method (LF-DFT) can be used to calculate the X-ray absorption spectra (XAS) and X-ray magnetic circular dichroism (XMCD) of lanthanide compounds from purely structural input.

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Horizon 2020 project SAMOSAFER granted

The EU Horizon 2020 program granted 3.5 million Euros to the research and innovation project SAMOSAFER, where PSI is one of the 14 project partners. The total budget of the project, inclusive own and in-kind contributions, is 4.5 million Euros. The aim of SAMOSAFER project is to develop and demonstrate new safety barriers and a more controlled behaviour in severe accidents of the Molten Salt Reactor (MSR). Three groups at PSI will be involved in the project: the LSM groups for Advanced Nuclear Systems (ANS) and Multiscale Materials Modelling (MMM) and the Severe Accidents Research group (Sacre) of LRT, focusing on redistribution of the source term in the fuel treatment unit of MSR and assessment and reduction of radionuclide mobility during accidental conditions.

Negative flat band magnetism in a spin–orbit-coupled correlated kagome magnet

Electronic systems with flat bands are predicted to be a fertile ground for hosting emergent phenomena including unconven- tional magnetism and superconductivity, but materials that manifest this feature are rare. Here, we use scanning tunnelling microscopy to elucidate the atomically resolved electronic states and their magnetic response in the kagome magnet Co3Sn2S2.

Ultrafast Radical Reactions: Comic art illustrating the reactivity of electronically excited xylyl radicals. Here the meta-xylyl radicals (M) sticks out and depletes twice as fast into the vibrationally hot ground state

How the methyl group position influences the ultrafast deactivation in aromatic radicals

The resonantly stabilized xylyl radicals (C8H9•) distinctively influence the combustion chemistry and, therefore, ultimately determine the performance of combustion engines. At that, the three different isomers (methyl group in ortho, para or meta position) exhibit notable differences at elevated temperatures. We have tracked down these dynamics on a femtosecond timescale by monitoring the response to preparation of a well-defined electronic and vibrational state.

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Electronic localization in CaVO3 films via bandwidth control

Understanding and controlling the electronic structure of thin layers of quantum materials is a crucial first step towards designing heterostructures where new phases and phenomena, including the metal-insulator transition (MIT), emerge. Here, we demonstrate control of the MIT via tuning electronic bandwidth and local site environment through selection of the number of atomic layers deposited.

Thermally activated two-dimensional artificial square ice with height offsets between nanomagnets.(A) Tilted-sample scanning electron microscopy (SEM) image of an artificial square ice with an introduced height offset h, which can be varied from sample to sample, until the competing interactions J1 and J2 are equalized and an extensive spin ice degeneracy is achieved. Scale bar, 400 nm. (B) XMCD image of the same artificial square ice array. Nanomagnets with moments pointing toward the incoming x-rays (i…

Emergent magnetic monopole dynamics in macroscopically degenerate artificial spin ice

Magnetic monopoles, proposed as elementary particles that act as isolated magnetic south and north poles, have long attracted research interest as magnetic analogs to electric charge. In solid-state physics, a classical analog to these elusive particles has emerged as topological excitations within pyrochlore spin ice systems. We present the first real-time imaging of emergent magnetic monopole motion in a macroscopically degenerate artificial spin ice system consisting of thermally activated Ising-type nanomagnets lithographically arranged onto a pre-etched silicon substrate. factors are observed.

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Structure and superconductivity in the binary Re1-xMox alloys

The binary Re1−xMox alloys, known to cover the full range of solid solutions, were successfully synthesized and their crystal structures and physical properties investigated via powder x-ray diffraction, electrical resistivity, magnetic susceptibility, and heat capacity. By varying the Re/Mo ratio, we explore the full Re1−xMox binary phase diagram, in all its four different solid phases: hcp-Mg (P63/mmc), α-Mn (I43m), β-CrFe (P42/mnm), and bcc-W (Im3m), of which the second is non-centrosymmetric with the rest being centrosymmetric. All Re1−xMox alloys are superconductors, whose critical temperatures exhibit a peculiar phase diagram, characterized by three different superconducting regions.

Matias Kagias

PSI Thesis Medal goes to Dr. Matias Kagias

The PSI Thesis Medal is awarded every second year to the best PhD thesis performed at the Paul Scherrer Institut. Matias received the prize for his excellent thesis entitled "Direct Self-Imaging Methods for X-ray Differential Phase and Scattering Imaging". Congratulations!

Lernender Betriebsunterhalt

Wege der beruflichen Integration

In der Berufsschule Scala werden Lernende, die eine IV-unterstützte Berufsausbildung auf Stufe eidg. Berufsattest oder eidg. Fähigkeitszeugnis absolvieren, gezielt gefördert. Sehen Sie, wie die Vorbereitungs- und Förderkurse auch unserem Lernenden, Sacha R., beim Erreichen seiner Ziele geholfen haben.

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User operation at SwissFEL has begun

The first user experiment has taken place the the SwissFEL X-ray free electron laser, officially inaugurating it as the newest user facility at the Paul Scherrer Institute. The experiment, led by Camila Bacellar from EPFL, investigated ultrafast electron transfer dynamics in a protein to try to identify the charge density re-localization after the protein absorbs a photon of UV light. The experiment was performed using the Alvra Prime experimental station, taking advantage of the integrated von Hamos X-ray emission spectrometer to perform both X-ray absorption and emission measurements on the Fe atom, which is located at the centre of the protein.