Scientific Highlights: Research Division "Research with Neutrons and Muons"
Pressure and temperature dependence of the laser-induced plasma plume dynamics
The influence of different background gases and substrate heating on the plasma plume dynamics from silver ablation is investigated by species selected time and space resolved imaging. The results provide a time-resolved understanding on how those process parameters affect the expansion: from a free expansion in vacuum with velocities exceeding 20'000 m/s to a very slow expansion in Ar at 1 × 10−1 mbar with arrival velocities of 280 m/s.
Electromagnon dispersion probed by inelastic X-ray scattering in LiCrO2
Lattice vibrations (phonons) in crystals are typically weakly interacting with the electronic and magnetic degrees of freedom, such as charge and spin fluctuations. Researchers of PSI together with collaborators from EPF Lausanne, Japan and USA discovered an unexpectedly strong coupling between lattice vibrations and spin fluctuations in the quantum magnet LiCrO2. The observed magnetoelastic waves or electromagnons carry both electric and magnetic dipole moment.
Intrinsic Ferromagnetism in the Diluted Magnetic Semiconductor Co:TiO2
Here we present a study of magnetism in Co0.05Ti0.95O2−δ anatase films grown by pulsed laser deposition under a variety of oxygen partial pressures and deposition rates. Energy-dispersive spectrometry and transmission electron microscopy analyses indicate that a high deposition rate leads to a homogeneous microstructure, while a very low rate or postannealing results in cobalt clustering.
Bulk superconductivity at 84 K in the strongly overdoped regime of cuprates
By means of magnetization, specific heat, and muon-spin relaxation measurements, we investigate newly synthesized high-pressure oxidized Cu0.75Mo0.25Sr2YCu2O7.54, in which overdoping is achieved up to p ˜ 0.46 hole/Cu, well beyond the Tc-p superconducting dome of cuprates, where Fermi-liquid behavior is expected.
The deuteron too poses a mystery
The deuteron — one of the simplest atomic nuclei, consisting of just one proton and one neutron — is considerably smaller than previously thought. This finding was arrived at by an international research group that carried out experiments at the Paul Scherrer Institute, PSI. The new result is consistent with a 2010 study by the same group, in which the researchers measured the proton and found a significantly smaller value than previous research using different experimental methods.
Structure and Conductivity of Epitaxial Thin Films of In-Doped BaZrO3‑Based Proton Conductors
Epitaxial thin films of the proton-conducting perovskite BaZr0.53In0.47O3−δH0.47−2δ, grown by pulsed laser deposition, were investigated in their hydrated and dehydrated conditions through a multitechnique approach with the aim to study the structure and proton concentration depth profile and their relationship to proton conductivity.
Effect of disorder on a pressure-induced z = 1 magnetic quantum phase transition
Pressure-induced ordering close to a z = 1 quantum-critical point is studied in the presence of bond disorder in the quantum spin system (C4H12N2)Cu2(Cl1−xBrx)6 (PHCX) by means of muon-spin rotation and relaxation.
Nanoparticle-Based Magnetoelectric BaTiO3–CoFe2O4 Thin Film Heterostructures for Voltage Control of Magnetism
Multiferroic composite materials combining ferroelectric and ferromagnetic order at room temperature have great potential for emerging applications such as four-state memories, magnetoelectric sensors, and microwave devices.
Magnetodielectric detection of magnetic quadrupole order in Ba(TiO)Cu4(PO4)4 with Cu4O12 square cupolas
In vortex-like spin arrangements, multiple spins can combine into emergent multipole moments. Such multipole moments have broken space-inversion and time-reversal symmetries, and can therefore exhibit linear magnetoelectric (ME) activity. Three types of such multipole moments are known: toroidal; monopole; and quadrupole moments. So far, however, the ME activity of these multipole moments has only been established experimentally for the toroidal moment.
Realizing topological stability of magnetic helices in exchange-coupled multilayers for all-spin-based system
Topologically stabilized spin configurations like helices in the form of planar domain walls (DWs) or vortex-like structures with magnetic functionalities are more often a theoretical prediction rather than experimental realization. In this paper we report on the exchange coupling and helical phase characteristics within Dy-Fe multilayers. The magnetic hysteresis loops with temperature show an exchange bias field of around 1.0 kOe at 10 K.
POLAR experiment successfully launched on Chinese spacecraft
The second Chinese space laboratory satellite Tian Gong 2 was successfully launched from the Jiuquan Satellite Launch Center on September 15th, 2016 at 22:04 BTC (UTC+8h). Among more than ten instruments onboard it also brought to space the only non-Chinese experiment POLAR - the hard X-ray polarimeter.
Investigating the Role of Strain toward the Oxygen Reduction Activity on Model Thin Film Pt Catalysts
Environmentally friendly energy conversion devices such as fuel cells are becoming more and more attractive. However, major impediments to large-scale application still arise on the material side, related to the cost and poor performance of the cathode catalyst. State-of-the-art electrocatalysts are all Pt-based materials, suffering from poor electrochemical oxygen reduction kinetics.
Robust metastable skyrmions and their triangular–square lattice structural transition in a high-temperature chiral magnet
Skyrmions, topologically protected nanometric spin vortices, are being investigated extensively in various magnets. Among them, many structurally chiral cubic magnets host the triangular-lattice skyrmion crystal (SkX) as the thermo- dynamic equilibrium state. However, this state exists only in a narrow temperature and magnetic-field region just below the magnetic transition temperature Tc, while a helical or conical magnetic state prevails at lower temperatures.
Blocking Gastric Lipase Adsorption and Displacement Processes with Viscoelastic Biopolymer Adsorption Layers
Delayed fat digestion might help to fight obesity. Fat digestion begins in the stomach by adsorption of gastric lipases to oil/water interfaces. In this study we show how biopolymer covered interfaces can act as a physical barrier for recombinant dog gastric lipase (rDGL) adsorption and thus gastric lipolysis.
Frequency-Induced Bulk Magnetic Domain-Wall Freezing Visualized by Neutron Dark-Field Imaging
We use neutron dark-field imaging to visualize and interpret the response of bulk magnetic domain walls to static and dynamic magnetic excitations in (110)-Goss textured iron silicon high-permeability steel alloy. We investigate the domain-wall motion under the influence of an external alternating sinusoidal magnetic field.
Magnetization Response of the Bulk and Supplementary Magnetic Domain Structure in High-Permeability Steel Laminations Visualized In Situ by Neutron Dark-Field Imaging
Industrial transformer cores are composed of stacked high-permeability steel laminations (HPSLs). The performance and degree of efficiency of transformers are directly determined by the magnetic properties of each HPSL. In this article, we show how the neutron dark-field image (DFI) allows for the in situ visualization of the locally resolved response of the bulk and supplementary magnetic domain structures in HPSLs under the influence of externally applied magnetic fields.
Laser spectroscopy of muonic deuterium
The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ-.
Search for the lepton flavour violating decay μ+→e+γ with the full dataset of the MEG experiment
The final results of the search for the lepton flavour violating decay μ+→e+γ based on the full dataset collected by the MEG experiment at the Paul Scherrer Institut in the period 2009–2013 and totalling 7.5×1014 stopped muons on target are presented.
Coexisting multiple order parameters in single-layer LuMnO3 films
Magnetoelectric multiferroics hold great promise for electrical control of magnetism or magnetic control of ferroelectricity. However, single phase ferroelectric materials with a sizeable ferromagnetic magnetization are rare. Here, we demonstrate that a single-phase orthorhombic LuMnO3 thin film features coexisting magnetic and ferroelectric orders.
Volume-wise destruction of the antiferromagnetic Mott insulating state through quantum tuning
RENiO3 (RE=rare-earth element) and V2O3 are archetypal Mott insulator systems. When tuned by chemical substitution (RENiO3) or pressure (V2O3), they exhibit a quantum phase transition (QPT) between an antiferromagnetic Mott insulating state and a paramagnetic metallic state. Because novel physics often appears near a Mott QPT, the details of this transition, such as whether it is first or second order, are important.