Transition énergétique

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. 

A team of researchers generates ultra-short spin waves in an astoundingly simple material. Due to its potential to make computers faster and smartphones more efficient, spintronics is considered a promising concept for the future of electronics. In a collaboration including the Paul Scherrer Institut, a team of researchers has now successfully generated so-called spin waves much more easily and efficiently than was previously deemed possible. The researchers are presenting their results in the journal Physical Review Letters (DOI: 10.1103/PhysRevLett.122.117202).

Researchers from the Helmholtz Zentrum Berlin (HZB) and the TOMCAT beamline have achieved a new world record in time-resolved tomography by measuring over 200 tomographies per second during heating of an evolving aluminium metal foam.

The intrinsic magnetic moment of a neutron, combined with its charge neutrality, is a unique property which allows the investigation of magnetic phenomena in matter. Here we present how the utilization of a cold polarized neutron beam in neutron grating interferometry enables the visualization and characterization of magnetic properties on a microscopic scale in macroscopic samples.

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. 

In order to clarify the mechanism behind this activity loss, in this study two high surface area iridium oxides were characterized under operando conditions using a novel setup that allows the quasi-simultaneous acquisition of anomalous small angle X-ray scattering (A-SAXS) and X-ray absorption spectroscopy (XAS) data.

Liposomes of specific artificial phospholipids, such as Pad-PC-Pad and Rad-PC-Rad, are mechanically responsive. They can release encapsulated therapeutics via physical stimuli, as naturally present in blood flow of constricted vessel segments. The question is how these synthetic liposomes change their structure in the medically relevant temperature range from 22 to 42 °C.

Aging populations and diabetics suffer from the effects of the glycation of collagen, the non-enzymatic formation of glucose bridges. While the secondary effects have been studied intensely, comparatively little is known on the direct effect of glycation on the structure of collagen. It has been demonstrated in this study, that the direct impact of glycation can be determined with sub-atomic precision, and that a model system based on abundantly available connective tissue of farm animals can be used for such studies. This opens new avenues for inspecting the effects of diabetes mellitus on connective tissues and the influence of therapies on the resulting secondary disorders.

Scientists have just nucleated ice in an X-ray microscope for the first time and they created chemical maps of those responsible.

A quantum spin liquid is a state of matter where unpaired electrons’ spins, although entangled, do not show magnetic order even at the zero temperature. The realization of a quantum spin liquid is a long-sought goal in condensed-matter physics.

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.

Water is a ubiquitous liquid with unique physicochemical properties, whose nature has shaped our planet and life as we know it. Water in restricted geometries has different properties than in bulk. Confinement can prevent low-temperature crystalliza- tion of the molecules into a hexagonal structure and thus create a state of amorphous water. To understand the survival of life at subzero temperatures, it is essential to elucidate this behaviour in the presence of nanoconfining lipidic membranes.