cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1820123
title: Lithium ion distribution in lithium aluminium phosphate and lithium germanium phosphate LISICON structured electrolytes

description: There has been a renewal of interest in lithium ion conducting solid electrolytes for use in lithium batteries. The ease of handling and scale-up, make oxide based systems, most industrially relevant in this respect. The present proposal seeks to use the advantages of neutron diffraction to examine the defect structure in two promising electrolyte systems with the LISICON structure using a combination of high resolution powder neutron diffraction and reverse Monte Carlo Modelling of high-flux neutron total scattering data. Details of the lithium ion distribution in lithium-rich LISICON analogues will be used to propose models of the conduction mechanism in these fast ion conductors.
DOI: 10.5286/isis.e.rb1820475
title: Probing the Evolution of Local Structure in Disordered Li-rich Cathode Materials for Li-ion Batteries using Neutron PDF

description: The next generation of Li-ion rechargeable batteries is contingent on the development of new positive electrode materials with a greater capacity to store charge. Highly ordered layered structures have been universally considered the best candidate materials, however, recently this foundational understanding has been questioned in light of the discovery of several new Li-rich disordered rocksalt structure with even higher capacities. However, all of these materials suffer from substantial capacity decay over prolonged cycling which poses a critical barrier to their implementation. Due to the poor crystallinity of these structures (crystallites ~5 -10 nm in diameter) local probe techniques are essential to understand any structural changes, wherein it is suspected the root of the problem lies. With the ability to differentiate Li, Ni and Mn, neutron PDF is the ideal candidate technique.
DOI: 10.5286/isis.e.rb1820479
title: Negative thermal expansion in the rutile phase of ZnF2

description: It has recently been discovered than the rutile phase of zinc fluoride shows negative thermal expansion along all three crystallographic axes. What is highly unusual about this material is that its structure consists of edge-sharing ZnF6 octahedra; in every case of a material containing cations and anions that shows negative thermal expansion, the structural polyhedra are connected only at corners. Sharing edges increases significantly the rigidity of the structure, which should mitigate against negative thermal expansion. We propose a total scattering experiment to be analysed by the Reverse Monte Carlo method to understand the nature of the structural fluctuations that lead to negative thermal expansion. To draw good conclusions, we plan also a parallel set of measurements on the rutile phase of titanium dioxide for comparison.
DOI: 10.5286/isis.e.rb1820594
title: Understanding Sulphur and Nitrogen-Aromatic interactions from liquid structure

description: Asphaltenes are a complex and problematic fraction of crude oil that can precipitate, alter wettability and stabilise unwanted oil-in-water emulsions. Asphaltenes have a high proportion of aromatic carbon and heteroatoms (N, S, O) and are generally thought to consist of one (or more) aromatic cores with alkyl side chains. Despite considerable effort, there is little consensus as to the key structural features involved in asphaltene aggregation. We hypothesise that sulfur contining molecules play an important role in promoting aggregation. In the proposed SANDALS experiment we will use neutron diffraction to characterise the liquid structures of sulphur containing molecule (thiophene), and mixtures of thiophene or pyridine with benzene. The measurements will have particular significance for the study of the structure in biological macro-molecules and crude oil asphaltenes.
DOI: 10.5286/isis.e.rb1820629
title: Temperature Effects in YIG Films Probed by PNR

description: Yttrium iron garnet Fe3Y5O12 (YIG) is the material of choice for spin Hall related effects, magnonics, inter alia and has been used in microwave applications for many years. This is mainly due to two properties: a) YIG is a wide band-gap insulator, so it has no free electrons to contribute to the thermal conductivity in the Seebeck effect or to shunt the electrical signal in the high spin orbit metals used to measure the inverse spin Hall effect, and b) YIG has a very small Gilbert damping (~10-4) with a narrow resonant peak.Despite its popularity the magnetic properties of thin film YIG are not understood. Our group has conducted a comprehensive study of this topic, and have three further questions we wish to answer.
DOI: 10.5286/isis.e.rb1900138
title: Compressible Liquids Part 2

description: Liquids are commonly known to be incompressible. However, a recently invented class of materials called Porous Liquids, which exhibit permanent porosity in the liquid phase, are likely to be compressible. These porous liquids, when under pressure (50-1200 Bar), appear to reduce in volume as the bulk liquid will forcibly occupy the cavities thereby reducing the total volume of the liquid. As the synthesised porous liquids can have up to ten percent free space, there is the potential for these porous liquids to undergo much greater reduction in volume than for conventional liquids (seemingly a 11% reduction) when pressure (300 Bar) is applied. In part one of the experiments we obtained very promising data of the first known compressible liquid. Part two will consist of reanalysing the system to better understand the parameters of this compressible liquid.
DOI: 10.5286/isis.e.rb1910056
title: Dynamical studies of incommensurate spin-density wave order in SrMn1-xWXO3 (X= 0.08, 0.1375 & 0.1625) using inelastic neutron scattering.

description: Our recent neutron scattering studies on SrMn1-xWXO3 exhibit rich structural and magnetic phases ranging from incommensurate charge (ICDW) and spin (ISDW) density wave modulations. The ISDW structure obtained from magnetic peak refinement of the neutron data exhibit moments approaching effectively even to zero. This indicates that ISDW structure arise either due to spatially modulated frustration of frozen-moments or due to spatially modulated fast local fluctuation of moments.  These two cases can be distinguished through inelastic neutron scattering experiments. The occurrence of scattered intensity at finite value of energy-transfer in E-Q space will confirm the dynamic nature of the spin-moments. On the contrary, absence  of scattered intensity at finite energy transfer in the E-Q space will confirm the frustration based ISDW structure.
DOI: 10.5286/isis.e.rb1910287
title: Hydrates in the binary system waterdimethylsulfoxide

description: Mixture of water and dimethylsulfoxide (DMSO) are useful as preservative liquids for the storage of living cells at very low temperatures, such that they can be revived and used in therapeutic procedures. For example, liver cells generated from a patient's own stem-cells can be stored, recovered and grown for later re-implantation using a cryopreservation protocol developed at UCL and evaluated in recent beam-time on IRIS. However, mixtures of water and DMSO are able to crystallise hydrates of DMSO when suitably annealed; the crystal structures and properties of these hydrates are unknown. It is essential for a complete understanding of DMSO solutions and how they respond to flash-freezing, devitrification and melting, that these hydrates be characterised. The objective of this work is to collect the first data on the crystalline hydrates of DMSO.
DOI: 10.5286/isis.e.rb1910487
title: Nuclear and magnetic structural investigation of single crystalline and powder α-CoV2O6 on WISH

description: Recent single crystal work on α-CoV2O6 has found a significant enhancement of the nuclear Bragg peaks on entering the low temperature antiferromagnetic states.  This proposal is aimed at understanding the origin of this either in terms of a k=0 structure or strong magnetoelastic coupling resulting in a release of extinction.  We propose to use WISH to measure both single crystals and also powders to obtain a single crystal magnetic refinement at low temperatures and also a structural refinement at higher temperatures.  This will be compared with powder measurements.
DOI: 10.25835/0042110
title: Condensation of non-Abelian $SU(3)_{N_f}$  anyons in a one-dimensional fermion model

description: Plots, data and Mathematica notebooks for the paper:\r\n\r\nDaniel Borcherding and Holger Frahm (2018): Condensation of non-Abelian SU(3)Nf anyons in a one-dimensional fermion model, J. Phys. A: Math. Theor. 51 495002 \r\nDOI: 10.1088/1751-8121/aaea9b \r\narXiv: 1808.05808\r\n\r\nand the doctoral thesis:\r\n\r\nDaniel Borcherding (2018): Non-Abelian quasi-particles in electronic systems. Gottfried Wilhelm Leibniz Universit\xe4t Hannover, Diss.\r\nDOI: https://doi.org/10.15488/4280
DOI: 10.5286/isis.e.rb1610004
title: Probing the electronic structure of uranium(IV) compounds by Inelastic Neutron Scattering

description: An understanding of the electronic structure of the actinide elements is one of the most intriguing and complex topics in contemporary chemistry. In particular the magnetic properties of uranium, the heaviest element that can be used in normal laboratories, are difficult to understand as crystal field splittings are of the same order as spin orbit couplings. Despite many reports in the literature over the past 7 decades this is still a hot topic. Here we aim to rationalise the anomalous low temperature magnetism of A4[U(NCS)8] (A = Et4N; Cs) whereby the low temperature magnetic moment is significantly different. In order to probe the low energy exciited states we will use Inelastic Neutron Scattering to directly measure these; this would be one of the very few such studies on any uranium compound.
DOI: 10.5286/isis.e.rb1610023
title: Characterization of heterogeneous solvent structure in a carbon capture fluid

description: We propose to use neutron scattering experiments to gain molecular level insight into an intriguing liquid structure observed in a water-free CO2-capture solvent.  Switchable ionic liquids (SWILs) are a promising class of CO2-separating solvents that entail an intrinsic heterogeneous, micro-domain solvent structure that changes size, shape and orientation of both molecular and ionic domains as a function of CO2 loading.  We aim to study interesting chemistry and controlling principles to determine how these gradient changes in molecular structure impacts CO2 chemisorption and diffusion of CO2 to and from the liquid.
DOI: 10.5286/isis.e.rb1610232
title: Temperature Dependence Study of the Local Magnetic Behaviour in Fe3C -Filled Nanowires (Follow on study from RB1520164)

description: Recent research in to Carbon Nanotubes filled with magnetic materials has produced someinteresting results that have the potential to bring about new computing technology. In particular one type of system referred to as a nanowire has shown particular promise. However, a deeper understanding of the fundamental magnetic properties is required to fully utilize these materials in novel applications. For the first time new fabrication methods have made it possible to study these systems using the MuSR technique which can provide vital information about the origins and behavior of the magnetic properties that conventional techniques cannot. Our key objectives in this proposal are to build on the novel result from the first MuSR studies, determine the origin of the magnetic properties and understand the role of the lattice crystal structure on these properties.
DOI: 10.5286/isis.e.rb1610312
title: Linking solvent structure to materials synthesis: Choline Chloride:Urea-Water effects on Nanostructured Ceria

description: In our recent work we have studied formation of nanostructured cerium oxides from the choline chloride:urea deep eutectic solvent (DES). We found that as water content in the solvent is increased from 1 mole equivalent to 10 mole equivalents the structure of the ceria formed in this system changes from nanospherical to rod-like and the performance of this material in catalysis improves dramatically, alongside an increase in the microporosity of the material. It appears that the solvent structure has a significant effect on the growth of ceria particles within this medium. In an earlier experiment we looked at the structure of this solvent with 1 and 2 mole equivalents of water, but now would like to extend this study to determine whether water in this DES is locally clustered thus affecting the shape of the growing nanoparticles.
DOI: 10.5286/isis.e.rb1610387
title: Spin-orbit transitions in CoV3O8

description: Strong orbital mixing resulting from local distortions in the crystal field can mix higher energy orbital states with the ground state.  We propose to characterise this mixing in CoV3O8 through the measurement of spin-orbit transitions.  CoV3O8 is based upon a strongly distorted octahedra around the Co2+ sites and displays a large ordered magnetic moment.  This material is currently being investigating as part of our exploratory study of the Cobalt-Vanadium phase diagram for new materials which display stepped magnetisation plateaus at low temperatures.
DOI: 10.5286/isis.e.rb1610491
title: Structure of polyaromatic hydrocarbons in solution

description: Polyaromatic hydrocarbons (PAHs) are small disk shaped molecules that are important to a number of active research areas. These include natural systems, such as asphaltenes, the heaviest fraction of crude oil, but also novel materials, such as discotic liquid crystals and nano-carbon solutions. They tend to aggregate through stacking of the disks  in the example of asphaltenes this can lead to numerous problems including loss of solubility, and subsequent deposition of blocking of pipelines. Here we study two small PAHs  naphthalene and phenanthrene  dissolved in benzene. This will further our fundamental understanding of how these important class of molecules dissolve and how they are structured in solution.  The data will also provide important benchmark data for the numerous groups who study these systems through molecular simulation.
DOI: 10.5286/isis.e.rb1610495
title: Structure of Petroleum Asphaltenes in Solution

description: Asphaltenes are the heaviest end of crude oil and are responsible for a multitude of engineering challenges. They can precipitate from the oil, depositing, blocking pipelines and fouling refinery equipment. They can also alter the wettability of an oil reservoir, reducing its productivity and can stabilise unwanted oil-in-water emulsions. Asphaltene molecules in crude oil aggregate together, forming loose, fractal aggregates. It is hypothesised that these aggregates are themselves built from denser nanoaggregates formed from stacking of the disk shaped molecules. In this experiment we will use combined small and wide angle neutron scattering to help understand the structure of the asphaltene molecules within the aggregate. The results will be compared directly with computer modelling approaches which can provide a more complete understanding of asphaltene aggregation.
DOI: 10.5286/isis.e.rb1610525
title: Muon Spin Relaxation detection of Spin-Polarized Conduction Electrons in Silicon

description: The proposed experiment is to observe optical spin-injection in Silicon through MuSR detection. An important part of research in next generation electronics focusses on the manipulation of spin as well as the charge of electrons in semiconductor devices. This may lead to improved integration of memory and processing resulting in higher density and lower heat dissipation. Silicon is an indirect bandgap material and it is generally accepted that optical spin-injection does not occur. We believe that it is possible in a narrow spectral range at the indirect bandgap and that it can be detected using the intrinsic spin sensitivity of MuSR. If MuSR is able to detect that spin-polarization, it will establish a particle-based probe for advancing Silicon spintronics. If optical spin-injection is observed, it will establish a powerful optical tool for studying spin-dynamics in Silicon.
DOI: 10.5286/isis.e.rb1700061
title: Incorporating outer membrane proteins in outer membrane models

description: The Gram negative bacterial outer membrane protects the bacterium from external toxins such as antibiotics. This is partially responsible for Gram negative bacteria becoming the greatest emerging source of antibiotic resistance. We are developing models of these bacterial outer membranes  and have successfully recreated the characteristic  lipid asymmetry and also the water filled periplasm. In order to fully recreate the membranes we will need to incorporate proteins and this proposal is our first attempt to create protein containing bilayers. We will incorporate the proteins into monolayers at the air water interface, a stage that is used in creating the final model. Then we will create bilayers using these proteins lipid monolayers. We will use INTER in order to test a range of conditions quickly and incorporate the successful methods into future experimental programmes
DOI: 10.5286/isis.e.rb1720187
title: Magnetic field switching of electric polarisation in Y-type Hexaferrites

description: The magnetoelectric Y-type hexaferrites demonstrate coupling between magnetism and electric polarisation in relatively small applied magnetic fields, and are hence candidate materials for use in future multifunctional devices. Of particular note is the observation that one can, without loss, invert the electric polarisation of the system with small magnetic fields - a non-trivial result that requires preservation of the antiferromagnetic domain structure throughout the switch. The magnetic mechanism that enables this inversion is not fully understood. In fact, suggested models are inconsistent with our initial observations. We propose to investigate this magnetic control of electric polarisation by performing a low field diffraction study on the WISH diffractometer. Understanding this phenomenon could in the future lead to novel methods of robust magnetoelectric switching.
DOI: 10.5286/isis.e.rb1720230
title: Light induced structural changes in hybrid lead-halide perovskites CH3NH3Pb(IxBr1-x)3

description: A controlled investigation of light-induced changes in hybrid perovskites is required to achieve stable operation of tandem solar cells and colour-tuneable light-emitting diodes. Recent reports have observed light-induced shifts in the optical bandgap under illumination with visible light, for which the origin is not understood, but thought to be partially due to halide ion migration. We propose to use muon spectroscopy to explore changes in the local structure of the lead-halide pervoskites, CH3NH3Pb(IxBr1-x)3 on illumination. Experiments will focus on samples continuously irradiated and compare the results with those made in dark conditions. Temperature dependent measurements will allow for the carrier lifetime and diffusion rates to be calculated. Preliminary measurements exploring the dynamics of the structural change will also be explored.
DOI: 10.5286/isis.e.rb1720269
title: Phonon-Liquid-Electron Crystal Behaviour in Cu8GeSe6

description: Thermoelectric devices enable the conversion of thermal energy into electrical power. The development of new materials is essential to enable large scale implementation of thermoelectric technology. Argyrodites are attractive candidates due to their remarkably low thermal conduction. The argyrodite Cu8GeSe6 is a particularly attractive thermoelectric material, as chemical substitution can result in a figure of merit above unity. This proposal seeks to investigate the structure of Cu8GeSe6  as a function of temperature, in order to gain a better understanding of the features that lead to low thermal conduction.
DOI: 10.5286/isis.e.rb1720283
title: Use of Negative Muons for elemental characterization of metallic archaeological finds of great historical and artistic importance.

description: Today, the conservation, preservation and study of cultural heritage is a field of concern within Italy and Europe. The muonic elemental analysis will make possible to discover patterns associated to the selection and provenance of raw materials, the manufacturing processes, the direction of past trading patterns and the persistence of particular cultural traditions. The idea behind this experiment is to optimize muon negative spectroscopy as a non-invasive and non-destructive probe for quantitative surface to bulk analysis (improving the data analysis and validating Monte Carlo Simulation) to be used in the archaeometric field for elemental characterization of metallic artifacts from the late Bronze-age of great historical and artistic importance found in different area of the Italy (Sardinia, Tuscany, Lazio and Campania regions) all affected by contact with the Nuragic population.
DOI: 10.5286/isis.e.rb1720300
title: Tunable Weyl and Dirac states in the nonsymmorphic compound CeSbTe

description: Within our previous proposal "Possible non-symmorphic, magnetic Weyl Semimetal in CeSbTe" we investigated the antiferromagnetic structure of CeSbTe. This material has a very rich magnetic phase diagram, and only small fields are necessary to push the system to a ferromagnetic phase. It is also possible that only small fields are necessary to align the Ce spins in different spacial directions. This is of interest because it allows to tune the electronics structure. CeSbTe belongs to the class of topological semimetals that are recently intensely studied because they can host new types of quasiparticles that can only exist in solid compounds and are unknown in high energy physics. Due to the different magnetic phases accessible, CeSbTe is a nice template system to access several novel topological states. We therefore wish to fully understand its magnetic phase diagram.
DOI: 10.5286/isis.e.rb1720468
title: Thermal expansion of persubstituited aromatics I: benzene.

description: 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 the crystalline state, via the characterization of the thermal expansion in C6H6, C6D6 and the per-alogenated benzenes in the temperature range 10 to 400K.
DOI: 10.5286/isis.e.rb1720473
title: Investigation of shake-down effects on residual stress redistribution in ship structures

description: The fact that residual stresses are redistributed or relaxed during operations shows the importance of understanding residual stress after a particular period. Elastic shakedown is a phenomenon in which the structure undergoes plastic deformation accompanied with a change in residual stress during the first few cycles followed by an elastic response. As a consequence, residual stresses are redistributed or relaxed. The principal aim of this experiment is to investigate the initial, as-welded distribution of residual stresses and their relaxation as a result of shakedown in T-joints. Dh-36, a typical ship structural steel is used to manufacture T-joints based on ship welding standard. This project has chosen an industrially relevant sample and load levels owing to the fact that these contributes to the variation in residual stress redistribution.