Scientific Highlighs Swiss Light Source (SLS) 2015

Three-dimensional rendering of two cells in their medium confined in a glass microcapillary of about 18 micron diameter. Colors indicate different organelle types with different mass densities.

Mass density distribution of intact cell ultrastructure

The determination of the mass density of cellular compartments is one of the many analytical tools that biologists need to unravel the extremely complex structure of biological systems. Cryo X-ray nanotomography reveals absolute mass density maps of frozen hydrated cells in three dimensions.

Virtual section through the middle of a seed from the Early Cretaceous exposing embryo and nutrient storage tissue. The tiny embryo shown in 3D has two rudimentary cotyledon primordia documenting the dicotyledonous nature of this extinct angiosperm. The fossil is reconstructed from synchrotron radiation X-ray tomographic microscopy measurements performed at the Tomcat beamline at the Swiss Light Source. Image: Else Marie Friis

Preserved Embryos Illustrate Seed Dormancy in Early Angiosperms

The discovery of exceptionally well-preserved, tiny fossil seeds dating back to the Early Cretaceous corroborates that flowering plants were small opportunistic colonizers at that time, according to a new Yale-led study.

First EIGER X 16M in operation at the Swiss Light Source

The macromolecular crystallography beamline X06SA at the Swiss Light Source, a synchrotron operated by Paul Scherrer Institute, is the first one in the world to upgrade its detector to an EIGER X 16M.

•Health Innovation
•8 min

3D nanostructure of a bone made visible

Biology
SLS

Bones are made up of tiny fibres that are roughly a thousand times finer than a human hair. Researchers at the Paul Scherrer Institute PSI have developed a new computer-based algorithm with which they were able to visualize the localised order and alignment of these nanostructures inside an entire piece of bone for the first time.

Schematic of a Weyl semimetal with spin polarized Fermi arcs on its surfaces connecting the projections of two Weyl nodes with opposite chirality.

Observation of Fermi-Arc Spin Texture in TaAs

The study of nontrivial topological semimetals (TSM) is an emerging subject, providing a new frontier in topological aspects beyond insulators. Here, we have investigated the spin texture of surface Fermi arcs in the recently discovered Weyl semimetal TaAs using spin- and angle-resolved photoemission spectroscopy. The experimental results demonstrate that the Fermi arcs are spin polarized. The measured spin texture fulfills the requirement of mirror and time-reversal symmetries and is well reproduced by our first-principles calculations, which gives strong evidence for the topologically nontrivial Weyl semimetal state in TaAs. The consistency between the experimental and calculated results further confirms the distribution of chirality of the Weyl nodes determined by first principles calculations.

Schematic of layer-specific electronic states in the bulk band gap of ultrathin magnesium oxide at the metal/oxide and the oxide/vacuum interfaces.

Excited states at interfaces of a metal-supported ultrathin oxide film

At the PEARL beamline, metal-supported ultrathin oxide films have been studied which are a class of materials of technological importance in various research fields such as catalysis, spintronics, or nanoelectronics.

•Future Technologies
•6 min

Electron’s cousin discovered after eighty-six-year search

SLS

In a series of experiments at the Swiss Light Source SLS, physicists from the Paul Scherrer Institute PSI have discovered a particle, the existence of which was predicted eighty-six years ago. It is a member of the particle family that also includes the electron, the carrier of electrical currents. The particle now discovered is massless and can exist only within a special class of materials known as Weyl semi-metals.

X-ray nanotomography aids the production of eco-friendly solar cells

Polymer solar cells are in the spotlight for sustainable energy production of the future. Characterization of these devices by X-ray nanotomography helps to improve their production using environmentally friendly materials.

Hydrogen atoms are light and can tunnel through a barrier. Tunnelling can be quenched by substituting them with deuterium, a twice as heavy isotope of H.

Controlling tunnelling in methane loss from acetone ions by deuteration

At the imaging Photoelectron Photoion Coincidence (iPEPICO) endstation of the VUV beamline evidence of H-atom tunneling was shown.

•Future Technologies
•7 min

Structure of concrete disease solved

SLS

When bridges, dam walls and other structures made of concrete are streaked with dark cracks after a few decades, the culprit is the so-called the concrete disease. Researchers from the Paul Scherrer Institute PSI and Empa have now solved the structure of the material produced in these cracks at atomic level - and have thereby discovered a previously unknown crystalline arrangement of the atoms.

•Future Technologies
•10 min

X-ray research in the UFO

SLS

At first glance, the Swiss Light Source SLS stands out as a striking building. The inside reveals a setting of cutting-edge research. A journey through a world where electrons race a slalom course and X-rays help decode proteins.

Figure caption: Sketch of the 3D Fermi surface of d-AlNiCo (left) and its experimental cross-sections in the indicated planes (right) showing vanishing pseudogap in the quasiperiodic directions.

Fermi states and anisotropy of Brillouin zone scattering in the decagonal Al–Ni–Co quasicrystal

Quasicrystals (QCs) are intermetallic alloys where excellent long-range order coexists with lack of translational symmetry in one or more dimensions. These materials have a high potential in application as a material for a solar cells, hydrogen storage applications, heat insulating layers, and others.

•Energy and Climate
•10 min

The key to charging a lithium-ion battery rapidly

Batteries
SLS

Lithium iron phosphate batteries are very durable and can be charged relatively quickly. Researchers from the Paul Scherrer Institute (PSI), ETH Zurich and Japanese car manufacturer Toyota reveal the reasons for these properties in a new study. The findings were made possible thanks to measurements using a new method at the Swiss Light Source (SLS) at PSI.

•Future Technologies
•12 min

In search of the smallest bit

Materials research
SLS

For increasingly compact storage media, magnetic areas – the memory bits – also need to become smaller and smaller. But just how small can a magnet be? Frithjof Nolting and his colleagues at the Paul Scherrer Institute investigate the surprising phenomena in the field of nanomagnetism.

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In Situ Serial Crystallography Workshop at the SLS

21 August 2015

The Macromolecular Crystallography group at SLS is organizing a three days workshop on in situ serial crystallography (http://indico.psi.ch/event/issx) between November 17 and 19, 2015. It will be dedicated in the presentation of a novel method facilitating the structure determination of membrane proteins, which are highly important pharmaceutical targets but are difficult to handle using 'classical' crystallographic tools. Designed for 20 Ph.D. students, postdocs and young scientists from both academia and industry, the workshop will consist of introductory lectures, followed by hands-on practicals on in meso or lipidic cubic phase (LCP) crystallization, on in situ serial crystallography data collection using a micro-sized beam and on data processing.

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Schematic diagram of vortex core reversal process. The vortex core magnetisation reverses its orientation when crossing a domain boundary (black down arrow to white up arrow).

Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core.

3D image of the buckyball structure investigated. In the right picture the distribution of Cobalt is shown in orange. (The solid line corresponds to 1 micrometre or 1 thousandth of a millimetre).

Element-Specific X-Ray Phase Tomography of 3D Structures at the Nanoscale

Recent advances in fabrication techniques to create mesoscopic 3D structures have led to significant developments in a variety of fields including biology, photonics, and magnetism. Further progress in these areas benefits from their full quantitative and structural characterization.

Figure: Left top, one of the XRPD measured patterns and the corresponding fit. Left bottom, the fitted size distribution (green bars) with the maghemite (shell) and magnetite (core) weight fractions as a function of diameter. Right, the corresponding saturation magnetization as a function of shell relative thickness for samples with the same average diameter. Inset, a sketch of a core-shell nanoparticle as modeled.

Correlating the Core-Shell Composition and the Surface Structure to the Magnetic Properties for Magnetite-Maghemite Nanoparticles in the 5-15 nm Range

Very small superparamagnetic iron oxide nanoparticles were characterized by innovative synchrotron X-ray total scattering methods and Debye function analysis, developed at the X04SA Materials Science beamline of SLS.

View of a Mn19 molecule on the gold surface. The surface-induced changes of the oxidation state and magnetic properties of the constituent Mn ions have been probed by X-ray absorption spectroscopy and X-ray magnetic circular dichroism.

Reduction of Mn19 Coordination Clusters on a Gold Surface

The surface-induced changes of the oxidation state and magnetic properties of Mn ion clusters have been probed by X-ray absorption spectroscopy and X-ray magnetic circular dichroism.

Schematics of the iMott spin detector attached to an ARPES analyzer.

Concept of a multichannel spin-resolving electron analyzer based on Mott scattering

The spin of electron plays a crucial role in many physical phenomena, ranging from the obvious example of magnetism, via novel materials for spintronics applications, to high-temperature superconductivity. Spin- and angle-resolved photoelectron spectroscopy (SARPES) gives the most direct access to the spin aspects of the electronic structure, but the one-channel detection principle of all presently available SARPES spectrometers severely limits their efficiency. A team of Swiss and Russian scientists has developed a revolutionary concept of a multichannel electron spin detector based on Mott scattering as the spin selective process and imaging-type electron optics.

(a) Rhombohedral distortion of the pseudocubic La1−xSrxMnO3 lattice; (b) GGA+U theoretical FS; (c,d) Experimental FS cross-sections, with the shadow contours manifesting the lattice distortion.

Fermi Surface of Three-Dimensional La1−xSrxMnO3 Explored by Soft-X-Ray ARPES: Rhombohedral Lattice Distortion and its Effect on Magnetoresistance

A research team led by scientists from the Swiss Light Source has for the first time established three-dimensional (3D) electronic structure of the perovskite compound La1−xSrxMnO3 connected with its colossal magnetoresistance. Instrumental for this study has been the use of the new experimental technique of soft-x-ray ARPES, available at the ADRESS beamline, with its intrinsically sharp definition of 3D electron momentum.

Multiresolution X-ray tomography, getting a clear view of the interior

Researchers at PSI have developed a technique that combines tomography measurements at different resolution levels to allow quantitative interpretation for nanoscale tomography on an interior region of interest of the sample. In collaboration with researchers of the institute AMOLF in the Netherlands and ETH Zurich in Switzerland they showcase their technique by studying the porous structure within a section of an avian eggshell. The detailed measurements of the interior of the sample allowed the researchers to quantify the ordering and distribution of an intricate network of pores within the shell.

•Future Technologies
•4 min

Nanometres in 3D

Nanotechnology
SLS

Scientists at the Paul Scherrer Institute and ETH Zurich have created 3D images of tiny objects showing details down to 25 nanometres. In addition to the shape, the scientists determined how particular chemical elements were distributed in their sample and whether these elements were in a chemical compound or in their pure state.

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Prepared for the SwissFEL

17. February 2015

For many years, PSI researchers have been testing experimental methods that will provide insights into novel materials for electronic devices. Using a special trick to make the Swiss Light Source (SLS) at PSI generate light with similar properties to that of PSI’s x-ray laser SwissFEL, the researchers were able to demonstrate that the experiments planned for SwissFEL are possible and they are now building an experimental station at SwissFEL.

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Left: Structure of BaFe2As2 with the motion pattern of the A1g phonon mode (red arrows). Right: Pump-induced change of diffraction intensity of the (1 0 5) reflection

Ultrafast structural dynamics of the Fe-pnictide parent compound BaFe2As2

Understanding the interplay of the various degrees of freedom such as the electrons, spins and lattice is essential for many complex materials, including the high-temperature superconductors.

•Future Technologies
•7 min

Batman lights the way to compact data storage

Materials research
SLS

Researchers at the Paul Scherrer Institute (PSI) have succeeded in switching tiny, magnetic structures using laser light and tracking the change over time. In the process, a nanometre-sized area bizarrely reminiscent of the Batman logo appeared. The research results could render data storage on hard drives faster, more compact and more efficient.

Magnetization dynamics inside a 5 µm x 5 µm structure.(a) Time-resolved PEEM images using XMCD as a magnetic contrast mechanism recorded at a given time delay t after the laser pulse and (b) extracted XMCD contrast as a function of the time delay t for three different ROI, defined in the inset image by the coloured area superimposed on the non-dichroic X-ray absorption of the structure. The 0° incoming laser direction with respect to the structure edge is indicated in the inset by the laser in-plane wave v…

Nanoscale sub-100 picosecond all-optical magnetization switching in GdFeCo microstructure

Ultrafast magnetization reversal driven by femtosecond laser pulses has been shown to be a promising way to write information. Seeking to improve the recording density has raised intriguing fundamental questions about the feasibility of combining ultrafast temporal resolution with sub-wavelength spatial resolution for magnetic recording. Here we report on the experimental demonstration of nanoscale sub-100 ps all-optical magnetization switching, providing a path to sub-wavelength magnetic recording.