cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1800100
title: Clarifying the role of acid and base dopants in the hydrogen-ordering phase transitions of ice

description: Using ISIS facilities, our team has discovered three new phases of ice: ices XIII, XIV and XV. These phases form in the presence of small amounts of hydrochloric acid. Yet, the role the acid dopant plays is still very poorly understood. In particular since the preparation of ice XI from the ordinary ice I requires base doping and acid doping is ineffective. Now, we have found using calorimetry and X-ray diffraction that ice XIII can also be prepared with lithium hydroxide doping. Since this is the first case where acid and base doping are effective, we now have the perfect system for finally clarifying the role of the dopants. In addition to complementary DFT calculations, the experimental key question is now if acid and base dopants facilitate the same structural pathways leading towards the same ice XIII end-state. This question can only be answered with neutron diffraction.
DOI: 10.5286/isis.e.rb1810080
title: Kinetics of the ordering transition in ice Ih; crystal structure and thermal expansion of ice XI

description: Below 80 K ordinary water ice (ice Ih) undergoes a phase transition in which the randomly oriented molecules in the crystal adopt an ordered orientation. This ordered form of ice is known as ice XI. In pure ice, the transition is expected to require ~ 100 kyr to complete. In planetary environments, such as the outer solar system, time is no issue, so it is likely that ice XI is very abundant in space. However, the transformation can be sped up with a molecular 'lubricant', such as KOH, which at low concentrations acts to catalyse the ice Ih to ice XI reaction. Even so, on the timescales of typical neutron diffraction studies, the transformation usually around half complete after 5 days. I propose a long-duration experiment (1-2 months) to prepare the most completely transformed ice XI specimen, which is essential for accurate characterisation of the structure and properties.
DOI: 10.5286/isis.e.rb1810174
title: Can water-in-supercritical CO2 nanodispersions be stabilized without the aid of fluorocarbon and ionic surfactants?

description: Recent SANS studies of an unusual headgroup (HG)-free, fluorocarbon (FC) surfactant (Nohead FC6-HC4) produced data that implied the formation of stable, W/CO2 nanodispersions (W/CO2NDs). With the compound Nohead FC6-HC4 having unusual surfactant architecture, the W/CO2ND formation is a surprising find with a significant potential impact in this science field. Due to the lack of a charged HG, this type of W/CO2ND could be a more practical and universal solvent, without the complex after treatments normally required to remove charged surfactants. Unfortunately, even though promising due to their lack of charge, these W/CO2NDs still contain expensive and bio-accumulative FCs. This proposal aims to find an answer to the question Can W/CO2NDs be stabilized without the aid of F-atoms and a HG?. This study explores W/CO2ND formation using FC- and HG-free compounds of various structures.
DOI: 10.5286/isis.e.rb1810451
title: Understand the role of dimensionality on heavy fermion physics and quantum criticality in CeCo2Ga8: A Muon Study

description: Dimensionality plays an important role in determining the anomalous non-Fermi liquid properties in heavy fermion systems. So far most heavy fermion compounds are quasi-two-dimensional or three-dimensional. CeCo2Ga8 shows a non-Fermi liquid behaviour in the resistivity and heat capacity at low temperature. Magnetization result suggests the typical behavior for a one-dimensional spin chain from 300 K down to 20 K, and first-principles calculations predict flat Fermi surfaces for the itinerant f-electron bands. These suggest that CeCo2Ga8 is a rare example of the quasi-one-dimensional Kondo lattice. We propose to carry out low temperature MUSR measurement down to 50 mK to study the non-Fermi liquid states on the MUSR spectrometer. This MUSR study, help us to understand the role of dimensionality on heavy fermion physics  and quantum criticality.
DOI: 10.5286/isis.e.rb1820006
title: Neutron Compton Scattering- augmented Neutron Diffraction

description: Here we propose to integrate the anharmonic BC method with NCS-determined NMD, using 3 different types of information obtained from 3 different sources: (1) ADPs, as the result of single crystal structure refinement using SXD data; (2)   from lattice expansion obtained from le Bail fits to measured VESUVIO powder diffraction patterns, and (3) NMDS obtained from Compton data recorded on VESUVIOAs a test system, we propose to measure Hexamethylenetetramine (HMT), (CH2)6N4. It is a relatively simple molecule with a number of industrial applications. Moreover, it forms a well-characterised crystal structure with well-known mode frequencies and the Gruneisen parameter values.
DOI: 10.5286/isis.e.rb1820090
title: The origin of the dissolution of cellulose in NaOH/urea aqueous solution at -12 degree centigrade

description: Cellulose is produced over tens of billions of tons every year in the world. It is the one of the most abundant natural polymer resources. Compared with petroleum-based polymers, cellulose has very excellent features, such as renewability, wide availability, low-cost, biocompatibility, biodegradability and carbon neutral, etc. So it is considered as a competitive candidate to replace petroleum-based polymer materials. Unfortunately, natural cellulose molecules are always close packed by inter-/intra-hydrogen bondings, and are very difficult to be dissolved in common solvent. In recent years, it is found that urea can improve the solubility and stability of cellulose in aqueous alkali solution. The dissolution mechanism and role of urea have not been understood clearly, so we propose to use Sandals to study the cellulose dissolution mechanism and the role of urea in the process.
DOI: 10.5286/isis.e.rb1820315
title: Deep Eutectic Solvents in Chemical Synthesis: Probing Solvent-Substrate Interactions

description: Volatile organic solvents are used in the majority of chemical syntheses but due to their adverse effects on health and the environment, replacements are sought. Recent work on deep eutectic solvents (DES) has demonstrated that these novel liquids can replace organic solvents and bring exciting advantages. In addition to being inexpensive, non-flammable and having a low volatility it has been shown that reactions using organolithium reagents in DES can be carried out at room temperature in air, in the presence of water - conditions that are normally incompatible with polar organometallic compounds. Reactions in DES also had improved yields and better selectivities than standard inert atmosphere protocols. Here we wish to probe DES-substrate and DES-product interactions for a model ketone used in an arylation reaction with phenyl-lithium to understand how DES promote these reactions.
DOI: 10.5286/isis.e.rb1820350
title: Multi-scale modelling of HCP alloys using peak profile analysis

description: Hexagonal close packed (HCP) alloys have a wide range of industrial uses, including within the nuclear industry and for aerospace applications.The properties of HCP alloys are highly dependent on the microstructure that develops during processing, such as texture, grain size, and defect structures. However, because current thermomechanical processing routes are not well optimised there are considerable potential improvements in performance to be made. This work will combine crystal plasticity modelling with novel characterisation methods to understand the deformation of magnesium and zirconium alloys. The shape and position of the diffractionpeaks, alongside the modelling, will allow us to determine details of the deformed microstructure not possible by other approaches. The work will also help us to develop more realistic peak profile analytical approaches.
DOI: 10.5286/isis.e.rb1820433
title: Probing the magnetic structure of transition metal pyrovanadate Fe2V2O7

description: We have synthesized and characterized a new member, namely Fe2V2O7 in the family of 3d transition metal pyrovanadate M2V2O7 (M =Mn, Fe, Co, Ni, Cu). M2V2O7 exist with a great variety of crystal structures, which are reflected in the richness of their physical properties. In this family, transition metal ion plays a crucial role in presence of partially filled (for M2+) and half filled (for V5+) d orbitals; and it is of interest to intensify studies in this direction with different transition metal. Fe2V2O7 crystallizes in monoclinic structure with P21/c space group and it shows two anomalies in the magnetization data below 25 K. Here, we are proposing to study temperature dependent magnetic structure of Fe2V2O7 by performing powder neutron diffraction on WISH which is important to get insight of physics behind the various diverse properties of these transition metal pyrovanadates.
DOI: 10.5286/isis.e.rb1820515
title: Probing the role of atomic and magnetic order in chemically substituted NiMnIn Heusler alloys for magnetic refrigeration

description: Ni-Mn based Heusler alloys are magnetic multifunctional materials currently under intense research efforts thanks to their unique coexistence of a reversible structural transformation and magnetically ordered states. Magnetic field induced giant reversible mechanical deformations are promising for new-concept sensors and actuators. Giant caloric effects, triggered by magnetic fields, mechanical stress or pressure, make them promising as novel refrigerants for solid state refrigeration. The structural and magnetic properties of these materials (critical temperatures, magnetic order and entity of the effects) can be finely tuned by composition in a wide range of substitutions: in this sense the degree of  atomic order and chemical homogeneity are key parameters. Taking control of these aspects is mandatory for further development and for exploiting these materials in practical applications
DOI: 10.5286/isis.e.rb1870041
title: Measurement of the total muonium emission yield from silica aerogel using musr method

description: The aim of the present beam-time request is to perform a direct measurement of the total muonium emission rate from silica aeeogel to vacuum including the region very close to the aerogel surface. Laser ionization of the thermal muonium is a good candidate for the ultraslow muon beam production needed for the muon g-2/EDM measurement as well as for special musr applications. We will use the relaxation of muonium spin precession as the measure of the muonium emission yield from several aerogel samples. The yield information is critical in choosing the target condition that gives the maximum muonium emission yield.
DOI: 10.5286/isis.e.rb1900023
title: Novel phases in spin ice accessed via the application of pressure.

description: On general grounds the combination of neutron scattering techniques and high pressure are expected to be a particularly useful set of probes of frustrated magnets. Frustrated magnets typically feature macroscopically degenerate ground states with exotic excitations. The most prominent members of the spin-ice group are Ho2Ti2O7 (HTO) and Dy2Ti2O7 (DTO), in which magnetism arises from localised rare-earth ions with a strong crystal-field anisotropy. These exchange interactions lead to the exotic behaviours which, in the case of spin ice materials, includes residual entropy, magnetic monopoles and a Coulomb phase.  Under applied pressure, spin-ice compounds on the pyrochlore lattice are predicted to display exotic magnetic behaviour that included an infinite-order multicritical transition between a Coulomb and an ordered magnetised state.
DOI: 10.5286/isis.e.rb1900041
title: Unraveling the magnetic structure of Na2RuO3

description: Special attention has been devoted to the honeycomb iridates (Na, Li)2IrO3, in which SOC, intrinsic geometric frustration, and other competing interactions favor a highly anisotropic Kitaev exchange interactions that stabilizes exotic ground states such as quantum spin liquids (QSL). While such novel ground state has not yet been realized, largely due to competing isotropic interactions (Heisenberg) that stabilize magnetic order and/or lattice distortions that relieve geometrical frustration, searches for Kitaev and related QSLs are still ongoing. In this context, we have recently grown the honeycomb ruthenate, Na2RuO3. Here we propose to unveil the crystal structure and magnetic ground state of Na2RuO3 by means of neutron powder diffraction. Along with our concurrent proposal submitted to MARI, we aim to pin down the nature of the magnetic interaction in Na2RuO3.
DOI: 10.5286/isis.e.rb1900054
title: Chipir commercial access: Airbus

description: Tests of power electronics for Airbus applications
DOI: 10.5286/isis.e.rb1210310
title: 1210310
DOI: 10.5286/isis.e.rb1510299
title: Inelastic neutron scattering study of a quantum frustrated undistorted fcc lattice with strong spin-orbit coupling

description: A new material, Ba2LuMoO6, has been proposed to be an example of a valence bond glass. It bears numerous similarities in bulk measurements to Ba2YMoO6, which was the first valence bond glass, and which was observed to have a singlet-triplet excitation using inelastic neutron scattering. However, recent muon spectroscopy results indicate differences in the dynamics of the two systems. We therefore propose to study Ba2LuMoO6 with inelastic neutron scattering using the Merlin chopper spectrometer, which is optimised for the study of weak scattering, as present in s=1/2 systems, and which will allow us to perform wide energy surveys via rep-rate mode for this first INS study.
DOI: 10.5286/isis.e.rb1520238
title: SANS Study of the interaction of model wax alcohols with non-ionic surfactants at different temperatures

description: The understanding of the plant wax-surfactant interaction process is crucial to the development of more effective pesticide and fungicide formulations, essential for improving food production whilst reducing environmental impact. It is widely recognised that the detergency actions of surfactants can can hugely influence the transport properties of both water and active ingredients through the waxy leaf surface, however the role of the different wax components is not well understood.The aim of this work is to study how long-chain alcohols and alkyl-esters (the main components that make up wheat and barley waxes) interact with non-ionic CnEm micelles. This study will enable us to determine how representative the alcohol and ester chains are of the reconstituted waxes as a whole and to observe the influence of these component chains upon the miceller shape and structure.
DOI: 10.5286/isis.e.rb1567502
title: Spin dynamics study in a quasi two-dimensional S = 1/2 triangular antiferromagnet, EtMe3P[Pd(dmit)2]2 by LF-µSR
DOI: 10.5286/isis.e.rb1610036
title: μSR studies of magnetism in alkali-doped polyaromatic hydrocarbons (PAHs)

description: Superconductivity with Tc=33 K has been reported in alkali-doped polyaromatic hydrocarbons (PAHs). The compositions and structures are unknown owing to the multiphase nature and low crystallinity of the samples. We have recently developed synthetic methods to afford phase-pure highly-crystalline binary alkali PAH salts. In particular, Cs(C14H10) is Mott insulating and comprises spin-½ antiferromagnetic chains of phenanthride radical monoanions. The absence of long-range magnetic order above 2 K renders it a model system of p-electron one-dimensional molecular quantum antiferromagnetism. With this proposal, we want to address the nature of the magnetic state down to mK temperatures using the ZF/LF muSR technique and search for the emergence or not of long-range antiferromagnetic order. Complementary measurements will be performed on the isoelectronic AFM analogue Rb(C14H10)(THF).
DOI: 10.5286/isis.e.rb1620081
title: Chemical control of structures and magnetic ordering of cobalt oxide chalcogenides - HRPD

description: The response of the magnetic ordering of layered cobalt oxide chalcogenides to changes in electron count will be investigated in detail following a preliminary experiment at ISIS. The topotactic deintercalation of coinage metals from Sr2CoO2Cu2Se2, Sr2CoO2Ag2Se2 and Sr2CoO2Cu2Se1.6S0.4 using an iodine solution will produce a series of compounds. The effect of composition on magnetic ordering will enable the robustness of two competing magnetic structures, and the competition between them, to the Co oxidation state to be probed. The combined use of OSIRIS and HRPD for obtaining structural and magnetic information has been shown to be effective for similar compounds.
DOI: 10.5286/isis.e.rb1620102
title: Structural phase transitions in ferroelectric layered perovskite oxides

description: Recent theoretical work has identified that oxygen octahedral rotations (OORs) in layered perovskites such as RuddlesdenPopper (RP) phases A2[An-1BnO3n+1] can generate noncentrosymmetry (piezoelectricity or ferroelectricity) by a hybrid-improper mechanism.  Our group has reported OOR-induced noncentrosymmetry in n = 1 RP NaRTiO4 (R=rare earth) [Phys. Rev. Lett. 112, 187602 (2014)].  We now extend our understanding of OORs to an n = 2 RP compound, Sr3Zr2O7.  Although Sr3Zr2O7 was previously reported to be centrosymmetric (space group Pmmm), we have observed second harmonic generation at 300 K, indicating the noncentrosymmetric nature.  We here propose variable-temperature neutron powder diffraction experiments on HRPD to resolve subtle changes in the crystal symmetry resulting from OORs and thus to identify unambiguously the thermally-induced phase transition sequence.
DOI: 10.5286/isis.e.rb1620184
title: Enhanced polarisation in platinum films adjacent to half-metallic Co2FeAl

description: The half-metallic Heusler alloy Co2FeAl (CFA) is a promising candidate material for high-frequency spintronic devices. As many of these device structures involve bilayers of CFA and Pt, and rely on properties arising due to this interface for their functionality, understanding the proximity magnetisation that may be induced in Pt by proximity to CFA is very important. The polarisation usually found in Pt is too small to be observable by PNR. However, we find evidence from conventional magnetometry and resonant x-ray scattering for an unprecedented large polarisation in Pt layers beneath CFA thin films. We intend to use magnetic scattering length density profiles extracted from PNR to confirm and quantify uniform half-metallicity in CFA, magnetisation corresponding to an integer multiple of the Bohr magneton per formula unit, and the very large polarisation of Pt layers adjacent to it.
DOI: 10.5286/isis.e.rb1710043
title: Investigation of lithium diffusion in spinel Li2NiGe3O8 and N-doped Li3+xV4-xNx ceramics using muon spectroscopy

description: We wish to perform muon spectroscopic experiments on materials from two ceramic systems that are of interest for possible solid electrolyte applications in lithium-ion battery devices: (i) Li2NiGe3O8 and (ii) N-doped Li3+xVO4-xNx. Muon spectroscopy will provide us with a means of determining the key parameters of Li diffusion (Li-ion diffusion rates and activation energies) in our paramagnetic ion-containing systems. Similar data cannot be obtained using any other technique. We request 5 days of beamtime on the EMU beamline to perform these experiments.
DOI: 10.5286/isis.e.rb1710430
title: Investigating the graphitisation behaviour of polycrystalline diamond at high temperature

description: Polycrystalline diamond is a man-made diamond material used for rock drilling and machining operations. Its vastly superior hardness to any other material allows it to cut through challenging materials such as rock, high-strength metals and carbon fibre composites whilst itself wearing away very slowly. However, at high temperature, it suffers from mechanical breakdown due to an unknown mechanism. It is suspected that one of its constituents, cobalt metal, reacts with the diamond causing it to convert to graphite. This experiment will aim to discover the temperature at which this begins by observing changes in the crystal structure of the diamond with neutron diffraction as temperature is increased. The stress put on the surrounding diamond material by this crystal structure change will also be measured and used to determine how the material breaks down at high temperature.
DOI: 10.5286/isis.e.rb1800096
title: Completing ChipIR high-energy data with thermal neutrons

description: In previous experiments at ChipIR we have measured and characterized the Single Event Effects (SEEs) produced by high-energy neutrons available at ISIS in different electronic devices (processors, FPGAs, memory, etc..) including object detection algorithms for automotive applications. In this proposal we intend to correlate the high-energy data with thermal neutron flux available at ALF/ROTAX. Modern devices, in fact, include Boron-10 in the doping. The interaction between B-10 and thermal neutrons is likely to generate alpha particles, which lead to SEEs, and is definitely worth being investigated.
DOI: 10.5286/isis.e.rb1810587
title: Catalysis  in Hydrogen-Bond Rich Porous Organic Materials

description: Hydrogen bonding (H-bonding) interactions are essential in biological and chemical processes, particularly in reactions catalysed by enzymes and small-molecule catalysts. Enzymatic processes are highly depend on the properties of the reaction environment, such as pH, presence of ions, organic solvents, and other proteins in cell media. Characterization and rationalization of relevant H-bondings in active sites is critical in designing and synthesizing new systems. Given that confined space of such organic materials is rich in H-bond donors and acceptors, the aim of this proposal is to obtain an insight into the role of H-bonding interactions between the NH3 molecules and the organic porous material using neutron scattering spectroscopy. Following this first step, this research will be extended to the incorporation of enzymes into the peptide-based porous organic polymers (PAAs, PIs).
DOI: 10.5286/isis.e.rb1810723
title: Solid-supported lipid bilayers for studying mechanosensitive ion channels: to tether or not

description: Bacterial membranes contain safety valves called mechanosensitive ion channels, which protect the bacterium from changes in the osmotic pressure of their environment. However, they also represent a possible achilles heal, which we may be able to exploit to help overcome the current rise in bacterial antimicrobial resistance. The ion channels could be actuated by a change in membrane tension caused by therapeutic molecules interacting with the membrane. We will develop a platform in which the ion channel is embedded in a model bacterial bilayer and either specifically tethered or not tethered at the surface. We will use the reflection of neutrons to probe if the addition of the therapeutic peptide causes a change in the curvature/tension of the bilayer in which the ion channels have been embedded and in doing so causes the channel to open, increasing the amount of water in the bilayer.
DOI: 10.5286/isis.e.rb1810776
title: Quasi-Elastic Neutron Scattering of Green Dioptase to Unravel the Motion of the Water Molecules

description: Green dioptase is a naturally occurring mineral, that has a deep green colour, similar to that of an emerald, and with a chemical formula of CuSiO3.H2O. The Cu lies in quasi-1D chains and has three nearest neighbours, two along the chains and one with the adjacent chain. Since there are only three Cu nearest neighbours, this has led to some speculation for more exotic forms of magnetism; however our current work has shown that the system behaves like a 3D magnet at low temperatures. One unresolved issue is the location and behaviour of the water molecules. We intend to rectify this and have so far conducted neutron diffraction experiments on single crystals to allow us to locate the protons and water molecules.  We have found evidence that the water molecules are dynamic this may affect other properties. Using Quasi-elastic neutron scattering we intend to probe this further.