5,796 Works

Self-assembly in ethyl ester sulfonate surfactants in the presence of electrolyte

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The methyl ester sulfonate. MES, and ethyl ester sulfonate, EES, are representative of a promising group of anionic surfactants which have the potential for improved performance and biocompatibility / biosustainability. Like LAS, SLES, and MES EES undergoes a transition from monolayer to multilayer adsorption at the air-water interface in the presence of multivalent counterions. Compared to MES and SLES there are some important differences. Previous studies on MES, SLES and LAS have shown that in...

Commissioning: Neutron phase-contrast imaging using edge illumination

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We aim at developing a new methodology to enable neutron phase-contrast imaging with extended sources and white beam. The approach here proposed is based on the edge-illumination concept where a beam of radiation is strongly modulated in amplitude immediately before it reaches the sample. The beam(s) created in this way are then aligned in such a way that approximately 50% of the intensity is lost on an absorbing edge(s) that is placed immediately before the...

Diffraction paten of a Heisenberg-Kitaev Quantum Spin Liquid candidate Li2RhO3

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We propose to continuous our investigation of the magnetic diffraction pattern of the potential Kitaev spin liquid compound Li2RhO3. Moderate spin orbit coupling in the Rh4+ ion is expected to results in a ground state doublet which in combination with the honeycomb structure of RhO6 edge-sharing octahedral, gives rise to highly directional Kitaev interactions. Our previous powder measurements of Li2RhO3 performed on WISH revealed the magnetic Bragg peak at |Q|=0.97 Å-1 suggesting that Li2RhO3 develops...

Dynamics of Solid Ionic Conductors: Na2Si2O5 and Li2Si2O5

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We would measure vibrational spectra for Li2Si2O5 and Na2Si2O5, as well as quasielastic neutron scattering (QENS) spectra for Na2SiO5. The measurement of phonon spectra in the entire Brillouin zone over the temperature range of 300-1300 K is required for characterizing the specific phonon modes relevant to the ionic conductivity and thermal expansion behavior. The measurements would help to identify the phonons which show significant changes as a function of temperature. In addition, we propose to...

Local ordering in copper antimony tin sulfide thermoelectrics

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Solid-state devices based on thermoelectric materials can directly convert heat into electricity and may be utilized to make use of waste heat, for example from industrial processes and vehicles. We have been investigating the thermoelectric properties of compounds based on copper antimony sulfide, Cu3SbS4 (famatinite). The system shows a dramatic increase in thermoelectric properties when Sn is substituted for Sb in the system Cu3Sb1-xSnxS4-y (0.0  x  1.0). We have collected neutron diffraction data...

Probing Magnetic Order in Defective Reduced Graphene Oxides by Means of mu-SR

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Reduced graphene oxide (rGO) with defective structure has shown interesting magnetic properties in the frame of room temperature ferromagnetism. The origin of the magnetic moments has been explained by NMR measurements originated from the existence of defects in the samples, not from possible impurities included in the system. Recent research has revealed that the increase of heating temperature and higher content of defects may enhance magnetization in the hysteresis curves. This may attribute to the...

Test of Neutron Effects On Commercial Off The Shelf FPGA

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The goal of these joint ChipIR/VESUVIO proposed experiments is to characterize the SEU occurrence on new generation FPGA caused by neutrons. We will focus on a Commercial Off-The-Shelf (COTS) component, in order to evaluate its robustness and its potential use in space environment in particular for micro and nano satellites. Due to their weight, power and budget limitations, and their low altitude operation, these satellites commonly use high performance COTS components.FPGAs represent a very interesting...

Direct observation of sodium ionic conduction in Na3PS4-based solid electrolytes

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All solid-state sodium ion batteries are potential low-cost alternatives to lithium ion batteries, especially for static and large-scale energy storage systems. The shift from liquid to solid electrolytes also promises major gains in battery safety. The critical challenge for all solid-state batteries is the lack of high conductivity electrolytes. In order to improve existing materials and develop new ones, we require not only a detailed knowledge of the structural properties of these materials, but also...

Quantum Entanglement of Neutron Spin, Path and Energy

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What does a quantum particle do when you are not looking at it? For a classical moving object, like a golf ball, we know its trajectory even when we are not looking at it. This is not the case with quantum particles, such as neutrons, whose behavior is described by quantum mechanics (QM) in terms only of probable outcomes of a measurement. Einstein argued that QM was unlikely to be a full theory because it...

Effect of oxidative stress on polyunsaturated lipid bilayers modulated by cholesterol and head group composition

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The exposure of biological membranes to reactive oxygen species is key for many pathological conditions, including inflammation, infection, or sepsis. Lipid peroxidation is known to deeply affect membrane properties such as structure or stability, but the specific roles of individual cell lipid components are complex and still not well understood. Here, we aim to study the structural consequences of lipid membrane oxidation induced by photoactivated TiO2 nanoparticles, of high pharmaceutical interest, and its dependence on...

Investigation of magnon dynamics of rare-earth garnet Ho3Fe5O12

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Rare-earth Iron garnets (RE3Fe5O12) have been in the focus of active research for the last five decades due to their fascinating properties, such as large magnetostriction, magneto-optical effects and possible application in spintronic. These compounds, model system illustrating the Neel theory of ferrimagnetism, has complex magnetic properties and influence of this complexity is not well studied. Hence, elaborate study of spin wave propagation on these ferrimagnetic insulator is required to provide microscopic models of its...

ChipIR Commercial Access Infineon OX07

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High-voltage power semiconductor devices, such as IGBTs, diodes and MOSFETs are susceptible to destructive failure due to terrestrial cosmic radiation (CR), notably the nucleon part. As a consequence, device development has to ensure adequate radiation hardness for every device technology. This aim can only partly be met by device and technology simulations and, therefore, also calls for extensive device tests. In order to reduce testing times accelerated irradiation tests at facilities with a nucleon energy...

Exploring grain - ice mantle interactions and dynamics for the extraterrestrial context

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Polycyclic aromatic hydrocarbons (PAHs), a wide class of organic molecules with multiply fused aromatic rings, are ubiquitous in the interstellar medium. In the condensed phase they are expected as precursors to small graphitic grains or condensation nuclei for icy grain mantles, from which they can be transformed into more complex organic and bio-relevant molecules. However, the paths for these processes remain relatively unexplored and little is known of the dynamic behaviour around these carbonaceous, icy...

Probing time-reversal symmetry breaking superconductivity in non-centrosymmetric SrAuSi3

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SrAuSi3 crystallizes in a BaNiSn3-type structure which has no inversion symmetry in real space and also a superconductor with a Tc of 1.54 K. SrAuSi3 includes Au as a principal constituent element, which is expected to favour strong spin-orbit coupling due to its heavy mass. The missing inversion symmetry along with strong spin-orbit coupling makes this material an ideal candidate to study for TRS breaking superconductivity. Here we propose to search for time-reversal symmetry breaking...

Temperature dependence of the hydrogen dynamics in an Iridium-hydride complex

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Transition metal hydrides are critically involved in many stoichiometric and catalytic organometallic reactions, such as hydrogenation. In these reactions a crucial step is the coordination of an intact H2 molecule to the metal centre and the ligand dynamics of the resulting coordination compound. We propose to investigate the temperature dependence of the Anisotropic Displacement Parameters obtained from multi-temperature single-crystal neutron diffraction on the octahedral complex trans-(P iPr3)2IrIH2(H2), in order to get valuable insight on the...

QENS OF HUMAN HAIR: EVALUATION OF WATER DYNAMICS IN HAIR SAMPLES SUBJECTED TO DIFFERENT COSMETIC TREATMENTS

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Human hair has been studied by x-ray diffraction and electron microscopy for many years, however a complete picture of its structure is still missing. Hair is a weakly scattering, disordered, and heterogeneous system. The use of thermal analysis, particularly DSC, for characterising damage and proposed repair of human hair is widely used by hair care scientists. However, even if DCS is a valuable tool to look for changes in both hair structure and the environment...

Understanding the network change in reversible photochromic hydrogels

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Photochromic devices are ones which change colour upon the irradiation of light. These devices can be used a sensors, logic gates and privacy windows etc. Here we show and example of a hydrogel that undergoes a reversible change from transparent to a dark brown colour upon the irradiation with UV light. An important feature of these hydrogels is that they do not fall apart upon multiple cycles of this irradiation, and whether the gel network...

High Energy Spin Excitations in Electron Overdoped NaFe0.7Ni0.3As

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The interplay between magnetism and superconductivity in iron-based high-temperature superconductors are of great interest in condensed matter physics research. These two properties can dramatically evolve with electron or hole doping in iron-based materials. To understand the interplay between magnetism and superconductivity and their co-evolution with doping across the phase diagram, magnetic excitation spectra obtained via neutron scattering are critical. Here we propose an inelastic neutron scattering experiment on high energy (mainly, also with low energy...

Magnetic Ground State of Pyrochlore Ruthenates

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We propose to clarify magnetic properties of Ca-doped Nd227 pyrocholore ruthenates, (Nd1-xCax)2Ru2O7., by changing the Ca concentration. The Ru spin forms a long-range ordered state for x=0 and the magnetic transition temperature is being suppressed with increasing the carrier concentration. A quantum critical point where the magnetic ordered state disappears is suggested to exist around x~0.20. We aim to determine the carrier doping dependence of a long-range ordered state of Ru spins clarifying a magnetic...

Free volume calibration of Polystyrene (PS) bulk above and below its glass transition temperature

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Free volume theory has successfully predicted and described all of the liquid-to-solid transitions in hard sphere system. However, in polymer system, the exact molecular picture of what is "free volume" is still vague. The only experimental observation which may be related to the molecular packing density and possibly the "free volume" is the small change in the scattering function, S(q) (or the pair correlation function), at q-1 in the range of monomer dimension. We propose...

High-pressure structure of magnetite nanoparticles

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One way in which nanoparticles may differ from bulk properties are in terms of their response to pressure, but at the present time there have been very few structural studies of nanoparticles under pressure. There is the possibility that nanoparticles will show different elastic properties under pressure. We are able to produce nanoscale magnetite, Fe3O4, reproducibly. We propose to study a range of nanoparticle sizes down to 5 nm of magnetite, and compare with bulk...

Muon spin relaxation investigation of triangular-lattice antiferromagnetic Fe3PO7

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A recent hot topic in condensed matter is the discovery and successive study of skyrmions in materials such as MnSi or Cu2OSeO3. By tuning the magnetic field and temperature, the magnetic defects form a periodic lattice, the skyrmion crystal. Part of the excitement stems from the possibility of harnessing the topological aspect of these spin textures as a promising avenue for spintronics technology. These special states sit near more conventional incommensurate helical structures. Recent work...

Thermal expansion of persubstituited aromatics I: benzene.

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Benzene is probably the most studied compound in the history of organic chemistry. Whenever a new experimental technique or theoretical method is being developed most of the time it is tested on benzene. This molecule can also be considered the parent compound for most molecular crystals based on C-H...pi interactions, in particular acenes. Aim of the present proposal is to understand the effect of isotope and chemical substitution on the vibrational properties of benzene in...

Singlet fission materials as active quantum dot ligands for photon multipliers

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Our research aims to develop plastic films that change the colour of the light that passes through them, not by absorbing certain wavelengths of light, as a simple colour filter would, but by converting light of one wavelength to another without losing any energy. Such a film, applied to a silicon solar cell, could make it up to 30% more efficient. To do this we need to make semiconductor nanocrystals, coat them with a very...

The high pressure structures of ammonium fluoride

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Ammonium fluoride is an ionic H-bonded analogue of ice. Its behaviour is thus of interest as a comparator for ice. This proposal is for beamtime to make the first neutron study of phase III of this material.

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