Data Science

Middle of February the upgraded CMS silicon pixel barrel detector has been moved from PSI to CERN and was successfully installed in the CMS experiment.

Spirals and helices are common motifs of long-range order in magnetic solids, and they may also be organized into more complex emergent structures such as magnetic skyrmions and vortices. A new type of spiral state, the spiral spin-liquid, in which spins fluctuate collectively as spirals, has recently been predicted to exist.

The macromolecular crystallography beamline X06DA-PXIII has reached 1,000 structures in the Protein Data Bank (PDB) on February 22, 2017.

In ionic surfactant micelles, basic interactions among distinct parts of surfactant monomers, their counterion, and additives are fundamental to tuning molecular self-assembly and enhancing viscoelasticity. Here, we investigate the addition of sodium salicylate (NaSal) to hexadecyltrimethylammonium chloride and bromide (CTAC and CTAB) and 1-hexadecylpyridinium chloride and bromide (CPyCl and CPyBr), which have distinct counterions and headgroup structures but the same hydrophobic tail.

“Switzerland at the Quantum Crossroads” outlines the current quantum science and technology landscape in Switzerland, explains the promises of this technology and outlines the required steps for Switzerland to leverage its leadership in this space.

We have developed a synthetic approach to highsurface-area chlorine-free iridium oxide nanoparticles dispersed in titania (IrO2-TiO2), which is a highly active and stable OER catalyst in acidic media. Operando X-ray absorption studies demonstrate the evolution of the surface species as a function of the applied potential, suggesting the conversion of the initial hydroxo surface layer to the oxo-terminated surface via anodic oxidation.

The RNiO₃ perovskites are known to order antiferromagnetically below a material-dependent Néel temperature TN. We report experimental evidence indicating the existence of a second magnetically ordered phase in TlNiO₃ above T_N = 104K, obtained using nuclear magnetic resonance and muon spin rotation spectroscopy.

The main threat to the reactor pressure vessel (RPV) operational safety is certainly the radiation damage that hardens and embrittles the steel it is made of. Four decades of research worldwide have allowed understanding and monitoring the phenomena that come into play. At the computational level, a simulation platform, PERFORM-60, has the ambitious aim of predicting the steel evolution for most RPV and operational conditions. It was initially elaborated in the frame of the EU project of the same acronym and is currently further developed to be the end-product of the on-going H2020 EU project SOTERIA. As a contribution of the Laboratory for Reactor Physics and Systems Behaviour (LRS) to SOTERIA, the platform has been rigorously assessed for the first time since its release on a real case study of a Swiss RPV. This critical assessment has been acknowledged by the community and serves as basis for improvements and future developments of the platform within SOTERIA.

SIM beamline scientist Carlos Vaz was recognized as outstanding referee for providing high quality peer review for the journals of the American Physical Society (APS).

The spinel FeSc₂S₄ has been proposed to realize a near-critical spin-orbital singlet (SOS) state, where entangled spin and orbital moments fluctuate in a global singlet state on the verge of spin and orbital order.

We investigated the depth dependence of current-induced magnetic fields in a bilayer of a normal metal (Au) and a ferrimagnetic insulator (Yttrium Iron Garnet—YIG) by using low energy muon spin spectroscopy (LE-μSR). This allows us to explore how these fields vary from the Au surface down to the buried Au|YIG interface, which is relevant to study physics like the spin-Hall effect.

On 7th February Dr. Christian Papp from University Erlangen (Germany) is visiting the SIM beamline and will give a Photon Science Seminar talk with the title: "In-situ Studies of the Reactivity of Model Catalysts: Surface Chemistry from flat surfaces to nanoparticles"

Researchers at PSI have developed a new unique miniaturized biaxial deformation rig, which allows to apply in-plane biaxial stress states with arbitrary stress ratios and to perform strain path changes on thin-sheet metals. The device is optimized for in situ usage inside a scanning electron microscope and at synchrotron beam lines.

We present a method for the precise determination of the full elasticity tensor from a single crystal diffraction experiment using monochromatic X-rays. For the two benchmark systems calcite and magnesium oxide, we show that the measurement of thermal diffuse scattering in the proximity of Bragg reflections provides accurate values of the complete set of elastic constants.

The Magnetism and Microscopy group has met for its annual retreat meeting in Lungern 11- 15.1.2017 (in the central mountain region of Switzerland) for extensive discussions on its science program. As for other years, after some general introductory lecture into the techniques used, current and future projects have been presented by the PhD students, postdocs, and scientists as well as from guests who collaborate with the group. Discussion went into the time where dinner has been prepared together, followed by some leisure activities on Saturday.

We present a detailed investigation of the temperature and depth dependence of the magnetic properties of the three-dimensional topological Kondo insulator SmB₆, in particular, near its surface. We find that local magnetic field fluctuations detected in the bulk are suppressed rapidly with decreasing depths, disappearing almost completely at the surface.

The pH-dependent structure and interaction of anionic silica nanoparticles (diameter 18 nm) with two globular model proteins, lysozyme and bovine serum albumin (BSA), have been studied. Cationic lysozyme adsorbs strongly on the nanoparticles, and the adsorption follows exponential growth as a function of lysozyme concentration, where the saturation value increases as pH approaches the isoelectric point (IEP) of lysozyme.