Paul Scherrer Institute

About: Paul Scherrer Institute is a facility organization based out in Villigen, Switzerland. It is known for research contribution in the topics: Neutron & Large Hadron Collider. The organization has 9248 authors who have published 23984 publications receiving 890129 citations. The organization is also known as: PSI.

Advances in artificial spin ice

Abstract: Artificial spin ices consist of nanomagnets arranged on the sites of various periodic and aperiodic lattices. They have enabled the experimental investigation of a variety of fascinating phenomena such as frustration, emergent magnetic monopoles and phase transitions that have previously been the domain of bulk spin crystals and theory, as we discuss in this Review. Artificial spin ices also show promise as reprogrammable magnonic crystals and, with this in mind, we give an overview of the measurements of fast dynamics in these magnetic metamaterials. We survey the variety of geometries that have been implemented, in terms of both the form of the nanomagnets and the lattices on which they are placed, including quasicrystalline systems and artificial spin systems in 3D. Different magnetic materials can also be incorporated to modify anisotropies and blocking temperatures, for example. With this large variety of systems, the way is open to discover new phenomena, and we complete this Review with possible directions for the future. Artificial spin ices are metamaterials displaying fascinating phenomena arising from the collective behaviour of nanoscale magnets. We review recent developments in terms of emergent magnetic monopoles, phase transitions, dynamics and geometries, and discuss future directions for research and potential applications.

Chemical characterization of element 112

Abstract: Element 112 was discovered at the Heavy Ion Research Laboratory in Darmstadt, Germany in 1996 A decade on, and some of its chemical properties have now been determined Irradiation of plutonium-242 with intense calcium-48 beams for three weeks produced two atoms of element 112 (not yet officially named, but commonly called ununbium), and that's enough to do some chemistry on if you are quick Chemically ununbium behaves as a typical element of the group 12 in the periodic table (which it shares with Zn, Cd and Hg) It is very volatile and forms a metallic bond with a gold surface An experiment has scrutinized two atoms of element 112, finding that it is very volatile and forms a metallic bond with a gold surface These characteristics establish element 112 as a typical element of group 12 The heaviest elements to have been chemically characterized are seaborgium1 (element 106), bohrium2 (element 107) and hassium3 (element 108) All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties4,5,6 The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12 Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury7,8,9 However, the production and identification methods10,11 used cast doubt on the validity of this result Here we report a more reliable chemical characterization of element 112, involving the production of two atoms of 283112 through the alpha decay of the short-lived 287114 (which itself forms in the nuclear fusion reaction12 of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface By directly comparing the adsorption characteristics of 283112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides

Synchrotron X-ray tomographic microscopy of fossil embryos.

Abstract: Fossilized embryos from the late Neoproterozoic and earliest Phanerozoic have caused much excitement because they preserve the earliest stages of embryology of animals that represent the initial diversification of metazoans. However, the potential of this material has not been fully realized because of reliance on traditional, non-destructive methods that allow analysis of exposed surfaces only, and destructive methods that preserve only a single two-dimensional view of the interior of the specimen. Here, we have applied synchrotron-radiation X-ray tomographic microscopy (SRXTM), obtaining complete three-dimensional recordings at submicrometre resolution. The embryos are preserved by early diagenetic impregnation and encrustation with calcium phosphate, and differences in X-ray attenuation provide information about the distribution of these two diagenetic phases. Three-dimensional visualization of blastomere arrangement and diagenetic cement in cleavage embryos resolves outstanding questions about their nature, including the identity of the columnar blastomeres. The anterior and posterior anatomy of embryos of the bilaterian worm-like Markuelia confirms its position as a scalidophoran, providing new insights into body-plan assembly among constituent phyla. The structure of the developing germ band in another bilaterian, Pseudooides, indicates a unique mode of germ-band development. SRXTM provides a method of non-invasive analysis that rivals the resolution achieved even by destructive methods, probing the very limits of fossilization and providing insight into embryology during the emergence of metazoan phyla.

Spatially and time-resolved magnetization dynamics driven by spin-orbit torques.

Abstract: Time-resolved X-ray microscopy reveals the mechanism and speed of current-induced magnetization switching of Co/Pt dots under the combined effect of spin-orbit torques and Dzyaloshinskii–Moriya interaction.

Characterization of surface processes at the Ni-based catalyst during the methanation of biomass-derived synthesis gas: X-ray photoelectron spectroscopy (XPS)

Abstract: Surface modifications during the production of methane from reformer synthesis gas over a commercial Ni/Al2O3 catalyst were investigated by quasi-in situ X-ray photoelectron spectroscopy (XPS) and other surface analytical techniques. Experiments of methanation reaction were done in the high pressure cell (HPC) integrated in the XPS system and under fixed-bed conditions. The interaction of the different reformer biomass-derived synthesis gas on the surface properties of the catalyst and on its activity under methanation conditions were studied on a nanoscopic level. Detailed description of changes in metal particle morphology and carbon deposit is presented. A mechanism of C-whiskers formation during long exposure to methanation conditions is described. The role of additional components in the gas mixture, such as CO2, H2O, CH4, C2H4, C2H2, C3H6 and C2H6, were studied in details. Furthermore, role of different nickel compounds such as oxides, hydroxides, carbides and carbonates are discussed.