Scientific Highlights
Priority access call for work on combating COVID-19
On January 30th, 2020, the WHO declared the recent outbreak of coronavirus disease 2019 (COVID-19), a public health emergency of international concern. It declared that there is an urgent need to improve our understanding of the newly identified virus and its possible future evolution as well as to contain the spread; to develop precise diagnostics and treatment, and to improve the public health response and patient care.
Short film of a magnetic nano-vortex
Using a newly developed imaging method, researchers were able to visualise the magnetic structure inside a material with nanoscale resolution. They succeeded in creating a short "film" consisting of seven movie frames that shows, for the first time in 3D, how tiny vortices of the magnetisation deep within a material change over time.
Soft X-ray Laminography: 3D imaging with powerful contrast mechanisms
3D imaging using synchrotron radiation is a widely used tool that allows access to the inner structure of complex objects. An international and interdisciplinary consortium of scientists from the Swiss Light Source (PolLux and cSAXs), the Friedrich-Alexander-Universität Erlangen-Nürnberg, and the University of Cambridge developed the new 3D imaging technique of Soft X-ray Laminography (SoXL). SoXL allows for the investigation of thin and extended samples while taking advantage of the characteristic absorption contrast mechanisms in the soft X-ray range, providing 3D information with nm spatial resolution.
Operando X-ray diffraction during laser 3D printing
Ultra-fast operando X-ray diffraction experiments reveal the temporal evolution of low and high temperature phases and the formation of residual stresses during laser 3D printing of a Ti-6Al-4V alloy. The profound influence of the length of the laser-scanning vector on the evolving microstructure is revealed and elucidated.
3D imaging for planar samples with zooming
Researchers of the Paul Scherrer Institut have previously generated 3-D images of a commercially available computer chip. This was achieved using a high-resolution tomography method. Now they extended their imaging approach to a so-called laminography geometry to remove the requirement of preparing isolated samples, also enabling imaging at various magnification. For ptychographic X-ray laminography (PyXL) a new instrument was developed and built, and new data reconstruction algorithms were implemented to align the projections and reconstruct a 3D dataset. The new capabilities were demonstrated by imaging a 16 nm FinFET integrated circuit at 18.9 nm 3D resolution at the Swiss Light Source. The results are reported in the latest edition of the journal Nature Electronics. The imaging technique is not limited to integrated circuits, but can be used for high-resolution 3D imaging of flat extended samples. Thus the researchers start now to exploit other areas of science ranging from biology to magnetism.
Evolution of Magnetic Order from the Localized to the Itinerant Limit
Quantum materials that feature magnetic long-range order often reveal complex phase diagrams when localized electrons become mobile. In many materials magnetism is rapidly suppressed as electronic charges dissolve into the conduction band. In materials where magnetism persists, it is unclear how the magnetic properties are affected.
Operando X-ray Characterization of High Surface Area Iridium Oxides to Decouple their Activity Losses for the Oxygen Evolution Reaction
The increasingly popular power-to-gas technology for the utilization of hydrogen as a clean energy vector involves the use of electrolyzers to convert water into H2 and O2. The oxygen evolution reaction (OER) is the least efficient among these processes, and a catalyst is required to speed up its kinetics at the high potentials (customarily ≥ 1.4 V vs. the reversible hydrogen electrode) at which the reaction takes place.
Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd2As2
Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi–long-range ferromagnetic fluctuations.
Molecular energy machine as a movie star
Using the Swiss Light Source SLS, PSI researchers have recorded a molecular energy machine in action and thus revealed how energy production at cell membranes works. For this purpose, they developed a new investigative method that could make the analysis of cellular processes significantly more effective than before.