Transition énergétique

Gamma-ray bursts (GRBs) are the strongest explosions in the Universe since the Big Bang. They are believed to be produced either in the formation of black holes at the end of massive star evolution or the merging of compact objects.

The effect of diameter reduction on the mechanical properties of cold-drawn nickel microwires has been analyzed by a combination of in situ X-ray diffraction and electron backscatter diffraction observations.

The solar water splitting process assisted by semiconductor photocatalysts attracts growing research interests worldwide for the production of hydrogen as a clean and sustainable energy carrier. Because of their optical and electrical properties, several oxynitride materials show great promise for the fabrication of efficient photocatalysts for solar water splitting. This study reports a comparative investigation of particle- and thin-film-based photocatalysts using three different oxynitride materials.

Dr. Yasin Ekinci, Head of the Advanced Lithography and Metrology Group and ad interim Head of the Laboratory for Micro and Nanotechnology, has been elected to the grade of Fellow of The International Society for Optics and Photonics (SPIE).

Dr. Mirjam van Daalen Chief of staff of the Photon Science Division, was mandated on the 1st of January 2019, by the State Secretariat for Education, Research and Innovation SERI as a member of the Swiss Delegation to the European Science Forum on Research Infrastructures ESFRI https://www.esfri.eu/.

Transition metal dichalcogenides (TMDs) are interesting for understanding the fundamental physics of two-dimensional (2D) materials as well as for applications to many emerging technologies, including spin electronics.

To trace the origin of time-reversal symmetry breaking (TRSB) in Re-based superconductors, we performed comparative muon-spin rotation and relaxation (μSR) studies of superconducting noncentro-symmetric Re_0.82Nb_0.18 (T_c=8.8 K) and centrosymmetric Re (T_c=2.7 K).

The research group of Prof. T.A. Jung at the University of Basel has reported on a new method that allows the physical state of just a few atoms or molecules within a network to be controlled.

A major milestone in the commissioning of SwissFEL has been reached: the first pump-probe experiments on proteins have been successfully carried out. Crystals of several retinal-binding proteins were delivered in a viscous jet system and a femtosecond laser was used to start the isomerization reaction. Microsecond to sub-picosecond snapshots were then collected, catching the retinal proteins shortly after isomerization of the chromophore.

We report the first observation of the parity-violating gamma-ray asymmetry A_γ^np in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory.

Magnetic domain walls can be reliably displaced by electrical currents, allowing for the fabrication of retentive magnetic memory elements without mechanically moving parts, such as e.g. the magnetic racetrack memory. Researchers in a joint collaboration between the PolLux endstation of the Swiss Light Source and the University of Leeds were able to investigate the dynamics of magnetic domain wall motion with a sub-ns time step, providing a substantial step forward towards the unraveling of the physical processes behind the current- and magnetic field-induced motion of magnetic domains.

Although ferromagnetism is known to be of enormous importance, the exploitation of materials with a compensated (for example, antiferromagnetic) arrangement of long-range ordered magnetic moments is still in its infancy. Antiferromagnetism is more robust against external perturbations, exhibits ultrafast responses of the spin system and is key to phenomena such as exchange bias, magnetically induced ferroelectricity or certain magnetoresistance phenomena.

A viable hydrogen economy has thus far been hampered by the lack of convenient hydrogen storage solutions for long hauls and transportation/delivery infrastructure. Current approaches require high pressure and/or complex heat management systems to achieve acceptable storage densities. Development of hydrogen storage solutions operating at near ambient conditions can mitigate the complexity, cost and safety perception issues currently hindering the hydrogen economy.

The Innovation Award on Synchrotron Radiation 2018 went to Dr. Christian David, also from the Paul Scherrer Institute, and to Prof. Alexei Erko, who recently moved from the HZB to the Institute for Applied Photonics (IAP) in Berlin-Adlershof.

Synchrotron-based X-ray tomographic microscopy of melanophores (skin pigment cells) of an amazingly well preserved 180 million years old ichtyosaur (extinct marine reptile similar to whales) contributed in a multidisciplinary investigation to the new findings published today in Nature.

In this paper, we present an e-nose for the detection of volatile compounds based on an array of six surface acoustic wave (SAW) resonators coated with five different polymers (i.e. polyepichlorohydrin, polyisobutylene, polyethylenimine, (hydroxypropyl)methyl cellulose, and poly(styrene-co-maleic acid) partial isobutyl/methyl mixed ester, plus an uncoated SAW device used as reference.

Heterogeneous and combined hetero/homogeneous chemical processes have attracted increased attention in many energy conversion systems, which include large scale power generation, microreactors for portable power generation, household burners, fuel processing technologies and automotive exhaust gas aftertreatment. Progress in such systems crucially depends on the development of catalysts with enhanced activity and thermal stability and on the comprehensive understanding of the fundamental processes occurring near gas solid reacting interfaces.

The compounds A₂Cu₃O(SO₄)₃(A=Na,K) are characterized by copper hexamers which are weakly coupled along the b axis to realize one-dimensional antiferromagnetic chains below T_N≈3K, whereas the interchain interactions along the a and c axes are negligible. We investigated the energy-level splittings of the copper hexamers by inelastic neutron scattering below and above T_N.

We have developed a new cruciform geometry with reduced thickness at the center, which allows reaching high plastic strain under equibiaxial loading. The novel thinning method results in excellent surface quality, suitable for electron backscatter diffraction (EBSD) and high-resolution digital image correlation (HRDIC) investigations. We performed an in-situ HRDIC study on a 304 austenitic stainless steel using the new cruciform geometry to follow the slip activity under uniaxial and equibiaxial loadings.

Catalytic materials are ubiquitously used in industrial processes to perform chemical reactions efficiently and in a sustainable manner. Nanoporous gold (npAu) is a monolithic sponge-like catalyst exhibiting a hierarchical structure with pores and connecting ligaments of typically 10 to 50 nm.