Scientific Highlights
Table-top soft x-ray lasers based on high-order harmonic generation (HHG)
Table-top soft x-ray lasers based on high-order harmonic generation (HHG) deliver routinely linearly polarized light. Many advanced applications including magnetic imaging would profit from a HHG source delivering in addition circular polarized light. In one of our recent work we present now an approach which provides intense soft x-ray radiation of high ellipticity. This source has given us the opportunity to realize the first magnetic dichroism experiment on a nickel sample at 18 nm (67 eV) with a table-top HHG source.
Successful start of the series production of the C-band accelerating structures for SwissFEL
A total of 104 C-band accelerating structures will be needed for SwissFEL. Each of these structures is about 2 m long and consists out of 113 copper cells that are manufactured with micrometer precision using ultra-precision diamond machining, which results in mirror-like surfaces. The main components are the couplers at the input and the output of the structure, and the copper disks. For both, couplers and disks, the series production was successfully launched at the end of 2014. Since then the Dutch company VDL and TEL Mechatronics in Trübbach, Switzerland, delivered already many sets of couplers and accelerating disks, respectively.
Pb pollution from leaded gasoline in South America in the context of a 2000-year metallurgical history
Exploitation of the extensive polymetallic deposits of the Andean Altiplano in South America since precolonial times has caused substantial emissions of neurotoxic lead (Pb) into the atmosphere; however, its historical significance compared to recent Pb pollution from leaded gasoline is not yet resolved. We present a comprehensive Pb emission history for the last two millennia for South America, based on a continuous, high-resolution, ice core record from Illimani glacier. Illimani is the highest mountain of the eastern Bolivian Andes and is located at the northeastern margin of the Andean Altiplano.
Interfacial dominated ferromagnetism in nanograined ZnO: a μSR and DFT study
Diamagnetic oxides can, under certain conditions, become ferromagnetic at room temperature and therefore are promising candidates for future material in spintronic devices. Contrary to early predictions, doping ZnO with uniformly distributed magnetic ions is not essential to obtain ferromagnetic samples. Instead, the nanostructure seems to play the key role, as room temperature ferromagnetism was also found in nanograined, undoped ZnO.
Non-Fermi Liquid Behavior Close to a Quantum Critical Point in a Ferromagnetic State without Local Moments
A quantum critical point (QCP) occurs upon chemical doping of the weak itinerant ferromagnet Sc3.1In. Remarkable for a system with no local moments, the QCP is accompanied by non-Fermi liquid behavior, manifested in the logarithmic divergence of the specific heat both in the ferro-and the paramagnetic states, as well as linear temperature dependence of the low-temperature resistivity.
Surface Aligned Magnetic Moments and Hysteresis of an Endohedral Single-Molecule Magnet on a Metal
The interaction between the endohedral unit in the single-molecule magnet Dy2ScN@C80 and a rhodium (111) substrate leads to alignment of the Dy 4f orbitals. The resulting orientation of the Dy2ScN plane parallel to the surface is inferred from comparison of the angular anisotropy of x-ray absorption spectra and multiplet calculations in the corresponding ligand field.
Prospective studies for SwissFEL experiments done at the SLS FEMTO station
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. read the full story)
Muonium in Stishovite: Implications for the Possible Existence of Neutral Atomic Hydrogen in the Earth's Deep Mantle
Hydrogen in the Earth's deep interior has been thought to exist as a hydroxyl group in high-pressure minerals. We present Muon Spin Rotation experiments on SiO2 stishovite, which is an archetypal high-pressure mineral. Positive muon (which can be considered as a light isotope of proton) implanted in stishovite was found to capture electron to form muonium (corresponding to neutral hydrogen).
Magnetic inhomogeneity on a triangular lattice: the magnetic-exchange versus the elastic energy and the role of disorder
Inhomogeneity in the ground state is an intriguing, emergent phenomenon in magnetism. Recently, it has been observed in the magnetostructural channel of the geometrically frustrated α-NaMnO2, for the first time in the absence of active charge degrees of freedom. Here we report an in-depth numerical and local-probe experimental study of the isostructural sister compound CuMnO2 that emphasizes and provides an explanation for the crucial differences between the two systems.
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.