cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1510139
title: IINS study of the terminating protons in the basic structural units of graphitising and non-graphitising carbons

description: Carbon blacks can be graphitised to different degrees, whereas glassy (vitreous) carbons, which are used as electrode material, in electronics and construction, and as crucibles, are resistant to graphitisation. Recently we have investigated the proton dynamics of type 1 glassy carbon as a non-graphitising carbon (maximum service temperature under argon: 1000°C) on TOSCA. The aim of this proposal is to extend the study to type 2 glassy carbons  (for maximum service temperature under argon: 3000°C) and to compare this to ordered and disordered acetylene blacks (very clean, high sp2 character).
DOI: 10.5286/isis.e.rb1510515
title: Structural characterisation of new Li- and Na-ion conductors for potential use as electrolytes or cathodes

description: Re-chargeable Li ion batteries play a key role in modern consumer electronics and may have an important part to play as energy storage devices in a low carbon economy of the future. Typical modern devices consist of solid state electrodes and an organic liquid electrolyte which is chosen for its high ionic conductivity and high electrical resistivity, but this component is flammable and presents a risk of fire or explosion, which is a particular handicap to the development of larger devices. The development of all solid-state batteries is therefore desirable but is dependent on the discovery of new solid state electrolyte materials with high Li-ion conductivity and low electronic conductivity. Here we will use neutrons to locate lithium within these materials something which cannot be done with X-rays.
DOI: 10.5286/isis.e.rb1510519
title: Structural origin of negative thermal expansion in ScF3

description: Scandium fluoride has recently been identified as a very simple example of a material showing negative thermal expansion over a wide range of temperatures. In particular, it might be thought to illustrate the classic mechanism of thermally excited octahedral rotations causing shrinkage of the crystal on heating. However, recent work has suggested that the dynamics are much more anharmonic than suggested by this picture. We are proposing a total scattering experiment, with results to be analysed by the Reverse Monte Carlo method. Previous successes with this method on perovskites suggest that this approach should be capable of giving a good structural understanding of the processes that lead to negative thermal expansion.
DOI: 10.5286/isis.e.rb1510530
title: Local structure of deuterated perovskite methylammonium lead iodide CD3ND3PbI3

description: Methylammonium lead iodide has recently been recognised as an excellent photovoltaic material, with energy conversion efficient of up to 15% with the prospect of gaining higher efficiencies. The crystal structure shows phase transitions involving ordering of the orientation of the polar methyl ammonium molecular cation. Indeed, at room temperature there is still disorder of this ion. The only technique to give a complete structural description of the disorder in these phases is neutron total scattering coupled with the Reverse Monte Carlo method. We are proposing to apply this approach in the study of this important material.
DOI: 10.5286/isis.e.rb1510584
title: New morphologies of functional metal oxide nanoparticles

description: The morphologies of metal oxide nanoparticles may be varied by imposition of an electric field during growth. These varying morphologies give improved efficiencies for gas sensing (monoclinic gamma-WO3) and photocatalysis (TiO2 anatase). We propose total scattering analysis of nanoparticulate TiO2 anatase and monoclinic gamma-WO3 grown in a variety of electric field conditions using NIMROD. Reverse Monte Carlo analysis of the data will enable us to correlate the properties of these materials with their local structure. Our results will give a greater understanding of the differences induced by imposing an E-field during the growth of these nanoparticulate materials and help address the wider issue of how to resolve the local structure of nanomaterials.
DOI: 10.5286/isis.e.rb1510596
title: Neutron Total Scattering Investigation of LaCoxMn1-xO3 Perovskites

description: The perovskite structure with general formula ABX3 describes many hundreds (if not thousands) of materials. Many have interesting and technologically important properties. The defining features of functional perovskites are deviations from the ideal, high symmetry structure. Crystallography, which determines the average arrangement of atoms in a material, can be used to explore these structural distortions but, if distortions occur on a length scale of only a few angstroms (over only a small number of repeat units of the crystal structure) they will not be visible. We will study a family of perovskites containing La, Mn and Co using the 'total scattering' technique which provides insight into the immediate local environment of the atoms in a material. This information will be vital to fully understand the relationship between the structure and properties of these materials.
DOI: 10.5286/isis.e.rb1561019
title: Time of flight neutron diffraction at pulsed neutron source using a side-on GEM based He-free neutron detector
DOI: 10.5286/isis.e.rb1561028
title: Gold and Silver fire gilding of copper/bronze objects
DOI: 10.5286/isis.e.rb1610055
title: Crystal and magnetic structure of the polar ferrimagnet BaCaFe4O7

description: Polar or non-centrosymmetric ferri(-o)magnets offer a plethora of potential technological devices; the inherent magnetoelectric effect can underpin both pyroelectric or multiferroic functionality. This will enable new functionality in electronic devices providing new benefits to consumers. For academic study, modulated magnetic structures, a prerequisite for skyrmion formation, can be stabilized via the Dzyaloshinskii-Moriya interaction (DMI) induced by the polar nature of the structure. These structures have been predicted to host a new type of magnons emerging from the multiferroic nature, the so called the electromagnon. These experiments are designed to probe the crystal and magnetic structure of a new candidate for these phenomena; BaCaFe4O7.
DOI: 10.5286/isis.e.rb1610105
title: Apatite-type Oxides for Energy Applications:  Local Structure and Structural Phase Transitions

description: Apatites are a large group of chemically and structurally flexible functional materials with important applications as solid electrolytes. The majority of known apatite materials are hexagonal, while others adopt related monoclinic or triclinic structures.The true symmetry is very important for apatite solid electrolytes: symmetry lowering results in defect trapping and decreased conductivity. Understanding what drives symmetry lowering will therefore help guide the chemical optimisation of these promising materials. Symmetry distortion mode refinements, which have not been reported for apatite-type materials to-date, together with local structure determination, will provide this insight.We request 3 days of POLARIS beam time for neutron total scattering experiments on a series of apatite materials, which adopt triclinic, hexagonal and monoclinic structures.
DOI: 10.5286/isis.e.rb1610229
title: H-bonding pattern in high-pressure polymorphs of carbohydrates

description: Carbohydrates are compounds most vital for all living organisms. Thanks to their multiple hydroxyl groups they can create numerous short-range interactions. Therefore they are the perfect study case to examine the nature of intermolecular contacts such as OH...O and CH...O hydrogen bonds. As it was recently shown for sucrose and glucose, two of the most common sugars, high pressure can significantly influence their crystal structure leading to phase transitions. High-pressure polymorphs of sugars were proven to have different H-bonding patterns in comparison to their ambient-condition forms. Yet, data collected till now were based only on X-ray diffraction experiments. Neutron diffraction is needed to precisely determine positions of hydrogen atoms in the structure and gain insight into the nature of high-pressure transformations of short-range interactions they are involved in.
DOI: 10.5286/isis.e.rb1610439
title: Ion distribution in light-emitting electrochemical cells

description: Semiconducting polymers are researched as alternatives to inorganic materials for use in electronic devices, such as solar cells or organic light-emitting diodes. Polymers are processable in solution, allowing for manufacturing of devices using cheap printing technology. Further, organic materials can be made biodegradable, and are made from inexpensive starting materials. Many polymers also conduct ions, a property which is used in devices such as the light-emitting electrochemical cell (LEC). An LEC is made from an organic semiconductor with mobile ions, between two electrodes. Upon operation, ions migrate in the polymer under applied bias, and in the region where positive and negative charges combine, light is emitted. Several aspects of the function of LECs are poorly understood, and we will use neutron reflectometry to monitor ion (re)distribution in LECs under operation.
DOI: 10.5286/isis.e.rb1610443
title: Unique disorder in the ammonia hydrates at high pressure

description: The ammonia hydrates are important systems for the understanding of the hydrogen bond and for models of the outer solar system. This proposal is for beamtime to explore the extent in composition space of the unique disordered molecular alloy structure of ammonia hydrates.
DOI: 10.5286/isis.e.rb1620231
title: Tuning the Magnetic Properties of γ-Fe2O3  Fe3O4 Thin Films for  Atom Trapping Applications

description: In this work we will investigate how the magnetic properties of nanometer thick iron-oxide films can be manipulated by heating them in air. Our preliminary results indicate that this can create remarkably large changes in the magnetic fields required to change the direction the film's magnetic moments point, increasing it by 100 % in some cases and decreasing it by 60 % in others. We will use polarised neutron scattering to try and understand these changes, with the ultimate aim of using these materials in novel devices.
DOI: 10.5286/isis.e.rb1700000
title: Transmission of curved and super-mirror coated Si-wafers
DOI: 10.5286/isis.e.rb1700057
title: Neutron tests of 16-nm technology node IC designs

description: This test will be part of commissioning program for ChipIR facility.  We plan to use multiple boards with custom designed test ICs to evaluate single-event performance of FF and logic circuits.  These ICs have been tested at Los Alamos National Labs in USA using their ICEHouse I facility.  The results from tests at ISIS will allow a meaningful comparison between the two facilities.  Our objective will be to obtain FIT rates for hardened and non-hardened FF designs.
DOI: 10.5286/isis.e.rb1710006
title: Alpha-Ti internal strain evolution under thermomechanical loading: influence of the temperature on the plastic anisotropy

description: The present proposal leans on the study of the elastoviscoplastic behavior of a polycrystalline alpha-Ti by neutron diffraction (ENGIN-X) in line with theoretical investigations (development of a more complete scale transition model): 3 dogbone-shaped samples will be charged in situ under incremental tensile strain at 4 different temperatures (ambient, 50, 150 and 250°C). To obtain a consequent data set for strain analyses, {hk.l} diffraction peaks will be followed along 2 principal directions. Collected patterns will provide the necessary data to establish a reliable model to understand and predict the thermomechanical behavior of alpha-Ti based alloys. It will especially enable the improvement of polycrystalline plasticity models through the integration of additional phenomena such as the contribution of the different deformation mechanisms to the macroscopic behavior with temperature.
DOI: 10.5286/isis.e.rb1710155
title: Residual stress measurements on cold expanded samples in the initial state and after fatigue cycling

description: Surface treatments such as cold expansion are widely used in industry in order to introduce compressive residual stresses in the bulk of the material in the vicinity of holes, up to 2mm beneath the surface. These compressive residual stresses are beneficial since they will prevent crack initiation from the surface and delay crack propagation originating from surface flaws for example. This experiment aims at characterising using neutron diffraction the residual stress fields below the surface in a Ni-base superalloy after cold expansion in order to incorporate the residual stresses within our models to predict its influence on initiation and crack propagation lives. In addition, residual stress relaxation after thermo-mechanical loading at high temperature will also be measured in order to assess the evolution of the beneficial residual stress during service and improve life prediction.
DOI: 10.5286/isis.e.rb1710202
title: Effect of temperature on the structure of model wax films as studied by neutron reflection

description: Cuticular wax films protect plants by mediating water and nutrient transport from the environment. Surfactant is a key ingredient in agrisprays that can promote the uptake of active ingredients across the wax films, but the exact molecular processes are little understood. In our previous work, we have demonstrated that by reconstituting wax films onto silicon oxide substrate, NR and other techniques can be used to characterise the structure of reconstituted wax films and their interactions with surfactants. In this proposal, we propose to use NR to study the model wax films comprised of representative wax ingredients focusing on examining the effect of temperature, with and without model surfactant C12E6. This work represents our continuous research endeavour to advance the science that could improve the performance of current pesticides and help develop better ones.
DOI: 10.5286/isis.e.rb1710304
title: Local structure in layered perovskite oxides - probing ion transport in fuel cell electrodes

description: Layered oxides are increasingly attractive as electrode materials in energy technology applications, such as fuel cells, electrolysers and permeation membranes. As the structures become more complex it is essential that a detailed understanding of the evolution of any cation ordering and related anion migration pathways is determined. Here we are focussed on the Ruddlesden-Popper series of oxides with a mixed A site (La and Pr)and wish to probe the temperature evolution of cation ordering, as well as the evolution of oxygen vacancies, which will provide insight into the oxygen transport pathways.
DOI: 10.5286/isis.e.rb1710407
title: Structural Disorder in the Quantum Spin Liquid Candidate YbMgGaO4

description: Quantum spin liquids are novel magnetic states in which quantum entanglement suppresses conventional magnetic order. Understanding the effects that stabilise such states is an important aim in condensed-matter physics. We propose to investigate structural disorder in the recently-synthesised quantum spin-liquid candidate YbMgGaO4, in which magnetic Yb(III) layers are separated by disordered Mg(II)/Ga(III) layers. We propose to use neutron pair-distribution function measurements to determine how Mg(II) and Ga(III) occupancies are correlated over short distances, and to reveal possible local distortions of the Yb(III) magnetic layers. These results will help to interpret our low-temperature inelastic neutron-scattering measurements, and to understand how structural disorder affects the quantum spin-liquid state in YbMgGaO4.
DOI: 10.5286/isis.e.rb1710459
title: Investigating time-reversal and pairing symmetry in topological superconductor NbxBi2Se3

description: NbxBi2Se3 is a potential topological superconductor candidate as it preserve Dirac surface dispersion and also superconducting at the same time. It belongs to the Eu representation of the D3d point group which allows the appearance of the chiral topological phase and breaks time-reversal symmetry (TRS) spontaneously. Indeed, Y. Qiu et al. has recently reported finite magnetization at zero field below the superconducting transition temperature (Tc) which can be attributed to TRS breaking fields. muSR technique is one of the most sensitive probe to detect such broken TRS unambiguously. Here we propose to study the magnetic and superconducting properties of NbxBi2Se3 by a combination of zero-field (ZF) and transverse-field (TF)-muSR measurements at the MUSR spectrometer. We ask for 4 days of MUSR beamtime to complete this proposed study.
DOI: 10.5286/isis.e.rb1720121
title: Dynamics in a new skyrmion spin texture in GaV4S(8-y)Se(y)

description: Topological physics was the subject of last year's Nobel Prize for Physics and over forty years after the groundbreaking work of Kosterlitz, Thouless and Haldane, remains an exciting and growing research area with the subject of skyrmions arguably its hottest topic. Skyrmions are topological objects which have been shown to exist in the spin textures of a range of magnetic materials. As we have recently demonstrated in our muSR work on these systems, muSR is a promising method for exploring the static and dynamics physics of skyrmion lattices (SLs). Here we plan to continue to exploit the strengths of ISIS muons to measure the dynamics associated with the skyrmionic series GaV4S(8-y)Se(y) which hosts a unique form of skyrmion spin texture.
DOI: 10.5286/isis.e.rb1720185
title: Self-assembly of Polyoxometallate Surfactants in Aqueous Solutions

description: Polyoxometallates (POM) are well defined transition metal clusters with a range of interesting catalytic, magnetic and optical properties. To make efficient use of these materials they are usually supported on other materials to provide a high surface area open network, allowing access to the POMs. The prospect of using solution self-assembly to structure POMs  directly or evenly dispersed within a silica matrix is therefore attractive, so we are studying the synthesis and organisation of POM-headed surfactants, with C12, C14 or C16 hydrocarbon tails. Preliminary conductivity and SAXS data suggest these micellize in dilute solutions but in X-ray scattering the electron-dense headgroup dominates the scattering. Here we propose to study the size and shape of POM-amphiphiles micelles alone and in mixtures with a nonionic surfactant using contrast variation to determine the structures.
DOI: 10.5286/isis.e.rb1720195
title: The role of spin-orbit coupling for the superconducting state in TrIrSi (Tr = Ti, Zr, and Hf)

description: Spinorbit coupling (SOC) is a fundamental interaction in solids that can induce unusual physical properties, from topologically non-trivial insulating states to unconventional pairing in superconductors. SOC also leads to several interesting physical phenomena such as Majorana fermions. TrTX (Tr = Ti, Zr, Hf, T = transition metals; X = P, As, Si) are known as a group of superconductors with a relatively high Tc = 15 K for MoRuP. We will focus on the Ir-compounds, which have strong SOC, arising from 5d-orbitals, to explore unconventional superconductivity. Recently Kase et al, [Super. Sci. Tech. 29 (2016) 035011] discovered a new series of 111 superconductor, TrIrSi with Tc = 1.4 K (Ti), 1.85 K (Zr), and 3.40 K (Hf). We propose to investigate the role of spin orbit coupling in the superconducting state using zero-field and transverse field muSR measurements on the MUSR spectrometer.
DOI: 10.5286/isis.e.rb1720268
title: Investigations of the magnetic structure in the isotropic S = 1 kagome antiferromagnet ND4Ni2.5V2O7(OD)2.D2O

description: Exotic electronic states are of great interest to fundamental science, such as the quantum spin-liquids (QSLs) which were theorised to behave like a sea of resonating spin states without preferential ordering, analogous to the liquid state. The best candidate materials for 2 dimensional QSLs are kagome magnets where the atomic magnetic moments make up a vertex-sharing lattice of triangles.  Away from the quantum limit, semi-classical frustrated magnets are predicted to host novel ground states, including spin-liquid states.  Here, we propose to study a new S=1 kagome antiferromagnet, ND4Ni2.5V2O7(OD)2.D2O, which shows evidence of competing magnetic interactions to produce an unconventional ordered ground state. We propose to use WISH to study short- and long-ranged spin structures and so to determine the role that frustration plays in its ground state properties.
DOI: 10.5286/isis.e.rb1720355
title: Interfacial Adsorption of Soluble Amino-Acid Based Surfactants in Mixtures with SDS and C12E6

description: Amino acid based surfactants have been known for many years, but so far few detailed studies have been carried out on their properties. We are using amino acids extracted from grain residues, otherwise used in animal feed, to prepare surfactants with amino-acid based headgroups. We aim to evaluate whether such feedstocks could provide a renewable source for such amphiphiles for use in emulsification, and formulations for delivery of active species. Here we propose a reflectivity study to investigate adsorbed monolayers of our amino acid-based soluble surfactants from binary mixtures  with model anionic and nonionic commercial surfactants. We aim to determine the extent of adsorption at water-air interfaces from pure and mixed surfactant solutions of these species, in competition with surfactants commonly used in formulations.
DOI: 10.5286/isis.e.rb1720381
title: Interaction of the intrinsically-disordered linker histone C-terminal tail with DNA.

description: In cells, the genome needs to be tightly packaged in the nucleus as "chromatin" while still allowing access to the cellular machinery responsible for gene expression. The first level of packaging involves the "core histone proteins, which form spools around which two turns of DNA are wrapped, a series of which gives rise to an array resembling "beads on a string". This is further condensed by "linker histone" proteins, one of which binds to each spool, arranging them into a thicker fibre. The precise way in which this is accomplished is, despite decades of research, still a hotly debated topic since linker histones have long tails that do not have a static defined 3D structure even when bound to the linker DNA that they are directly responsible for condensing, thus conventional diffraction-based methods fail. We aim to use SANS for this important piece of the chromatin structure puzzle.
DOI: 10.5286/isis.e.rb1510086
title: Crossover between diffusive and ballistic transport regimes in the S=1/2 Heisenberg antiferromagnetic chain SrCuO2

description: The question of whether the spin transport in an S=1/2 Heisenberg antiferromagnetic chain is ballistic or diffusive remains intensely discussed theoretically and studied experimentally. While spin transport in an integrable spin-1/2 chain would normally be expected to be ballistic, a number of experiments have found evidence for either type of transport of different systems and even cross-over regimes in certain systems. These findings can be explained in the context of recent theoretical work by Sirker et al. [1] who argue that both channels are present, with a cross-over taking place at an energy scale determined by the magnetic exchange and temperature. Here we propose to study the spin transport in the highly-ideal spin-1/2 chain SrCuO2, which due to its very large exchange constant (J=2100 K) should allow sensitive tuning between the two competing regimes in large magnetic fields.