cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1610313
title: Neutron scattering study on the honeycomb Heisenberg-Kitaev magnet alpha-RuCl3

description: The experimental realization of a Heisenberg-Kitaev model on the honeycomb lattice has been a major topic in a condensed matter physics, because the model predict a novel quantum spin liquid ground state and unusual magnetic phases induced by spin-orbit coupling and electronic correlation. The newly discovered alpha-RuCl3 has strong indications that it lies in proximate to a Kitaev spin liquid phase. Our preliminary inelastic neutron scattering result at MERLIN reveals a broad continuum and an abnormal dispersion of spin excitation at low energy transfer region but detailed nature is not conclusive. Using relatively good resolution and flux of LET beamline, we will clarify novel magnetism related to the Heisenberg-Kitaev model.
DOI: 10.5286/isis.e.rb1610390
title: Quantum dynamics in a J_eff=1/2 isotropic triangular-lattice antiferromagnet in applied field

description: This proposal is part of our research programme to explore the spin dynamics of strongly-frustrated quantum magnets. A canonical model is the spin-1/2 triangular antiferromagnet for which theoretical predictions for quantum dynamics effects leading to roton-like soft minima in the dispersion relation and extended scattering continua remain experimentally unexplored. In recent single-crystal measurements on LET we found that Ba3CoSb2O9 is a unique realization of such as system with i) strong renormalization of the spin-wave dispersion relation and zone-boundary soft modes ii) unexpectedly strong continuum scattering at intermediate to high energies. Here we propose to measure the magnetic field and temperature dependence of the dispersions and continuum scattering to compare with theories of quantum dynamics and distinguish between two-magnon and two-spinon continuum scattering.
DOI: 10.5286/isis.e.rb1610463
title: Asymmetric diffusion of water into bicontinuous cubic lipid nanomaterials using D2O / SANS

description: In this proposal we will investigate hypothesized asymmetric diffusion of water into lipid cubic (QII) phases. This asymmetric diffusion, which is relevant to the behavior of QII phases in drug delivery and mesoporous metal templating, was hypothesized fifteen years ago; while there are several pieces of data indirectly supporting the suggestion, we propose to produce the first direct experimental evidence using small-angle neutron scattering (SANS) with H2O / D2O contrast.
DOI: 10.5286/isis.e.rb1620168
title: Martensite Variants and elastic Constants of Co-Ni-Ga Shape Memory Alloys

description: Pseudoelastic Co-Ni-Ga high-temperature shape memory alloys are characterized by a wide range of tunable transformation temperatures and lower processing costs compared to conventional Ni-Ti-X HT-SMA which renders them useful for high-temperature applications in automotive and aerospace industries. In recent studies the fatigue behavior of Co-Ni-Ga single crystals was analysed by TEM and neutron diffraction. It was revealed that functional fatigue is dependent on two processes: increasing defect density and chemical ordering of Co, Ni and Ga. However, two temperature dependent aspects of fatigue behavior remain to be clarified: martensite variant selection under tensile and compressive load and elastic constants of both austenite and martensite. In situ neutron single crystal diffraction is our technique of choice as it allows to reliably investigate both aspects at the same time.
DOI: 10.5286/isis.e.rb1620225
title: Iron Oxide Nanoparticle Interactions with Lipid Bilayers in a Magnetic Field

description: Iron oxide nanoparticles are one of the first nanomaterials to be approved for use in the body. However, research into particle binding and incorporation to, as well as destabilization of, lipid and cell membranes is in its infancy despite its importance. Here, we propose to study the structure and destabilisation of the lipid bilayer in contact with IONPs using neutron reflection. The use of a magnetic adsorbent allows us to study the effect of an increasing static magnetic field perpendicular to the interface to either attract or repel the adsorbent from the lipid bilayer. The effect of an induced localised heating of the bilayer with an oscillating magnetic field will also be studied.
DOI: 10.5286/isis.e.rb1620273
title: Hydrogen diffusion in Palladium-Silver membranes measured by QENS

description: Hydrogen selective membranes based on palladium are important for technological processes such as isotopic separation and gas purification.In general, a Pd membrane when hydrogenated becomes brittle after a certain number of cycles of the α-β hydride transformation due to the subsequent lattice expansion. On the contrary, in Pd-Ag alloys, the lattice has been already expanded by the effect of Ag substitutional atoms, and so it is much less influenced by hydrogen uploading and, consequently, less brittle than in the pure Pd case Recently elastic and inelastic neutron scattering measurements were performed at ILL (D1B) and ISIS (MARI) to assess H occupancy and PDoS. H diffusivity at micro-scale is important to be measured for a thorough characterization of these materials. We propose a QENS measurement on OSIRIS at the same (T,p) of the MARI and D!B experiments.
DOI: 10.5286/isis.e.rb1620284
title: High Pressure Cation Ordering in ScVO3, InVO3 and the Sc(1-x)LuxVO3 Solid Solution

description: We propose an investigation of highly tilted AVO3 perovskites. These phases are only accessible under high pressure. We propose to follow the bixbyite to perovskite high-P phase transition at elevated temperatures and to explore potential high-P phases for InVO3. Cation disordered bixbyite phases provide access to cation ordered high-P phases with strained coordination environments. For example, extreme VO6 octahedral tilting causes long range magnetic ground state ordering in ScVO3. InVO3 has only been made as a bixbyite phase; however, at high-P a cation ordered perovskite similar to ScVO3 is expected. Ex-situ experiments have not led to an ordered InVO3 phase, we believe this is due either to not knowing the appropriate P-T combination for the ordering process, or that the transition is reversible. In-situ experiments are therefore required to explore the cation ordered phase of InVO3
DOI: 10.5286/isis.e.rb1620294
title: In situ D2 sorption in NaxLi6-xC60

description: Sodium and lithium intercalated C60 have been recently demonstrated to be a new class of hydrogen absorbers thanks to their capacity to dissociate H2 molecule at moderate pressure and temperature through a spill-over like effect. Pure phase of Li6C60 can store up to 5 mass% H2 at 100 bar with an onset temperature of 270 °C.During the last 4 years we successfully studied the in situ gas sorption by means of neutron powder diffraction at ANSTO (Sydney,AU). More recently, we also investigated the mixed phases NaxLi6-xC60, in order to find the best compromise between kinetics and absorption. Unfortunately, the low pressure allowed in ANSTO facility (P &lt; 60 bar D2) significantly limited the hydrogenation window to less than half of the maximum achievable value. This permitted us to investigate only the first stages of H2 absorption, while the complete process remained an open question.
DOI: 10.5286/isis.e.rb1620306
title: Determining the Hamiltonian of a New Quantum Spin Ice Material

description: Pr2Hf2O7 is a potential quantum spin ice compound. Compared to the classical spin ice ions Ho3+ and Dy3+, Pr3+ has weaker Ising anisotropy and significant XY terms leading to monopole fluctuations in the ground state. Pr2Hf2O7 does not develops long-range magnetic order down to the lowest measured temperature of 0.1K and while its excitations display pinch point like features at low energy transfers the they broaden significantly at higher energies suggesting enhanced dynamic correlations consistent with quantum spin ice. Here we wish to determine the Hamiltonian of Pr2Hf2O7 by using LET to measure the excitations in a magnetic field strong enough to suppress fluctuations and give rise to spin-wave excitations which can then be modelled and fitted to extract the couplings. This will provide a better understanding of Pr2Hf2O7 and a starting point from which to model the monopole dynamics.
DOI: 10.5286/isis.e.rb1620355
title: Magnetic Excitations of a New Heisenberg-Kitaev Quantum Spin Ice Candidate

description: We propose to measure the magnetic excitation spectrum 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. The resulting lattice is strongly frustrated and might be the reason why no long-range magnetic order has been found in this compound. Our goal is to measure the excitation spectrum which will be used to determine the values of the interactions and search for the anticipated fractional excitations by comparison to various theoretical models.
DOI: 10.5286/isis.e.rb1620439
title: Structure, thermal expansion and vibrational properties of ammonium bicarbonate, (ND4)DCO3

description: Ammonium carbonates, sensu lato, have relevance to carbon capture schemes and as potential hydrogen storage materials. These compounds occur on Earth as minerals and, since ammonia is thought to exist on icy planetary bodies, as 'rock-forming' minerals in the colder reaches of the solar system. Surprisingly little work on the structures and properties of these materials has been done; such work is essential for accurate modelling of icy planetary interiors. Having done high-pressure work on ammonium bicarbonate, and complementary DFT studies, this work aims to characterise to high precision the structure, thermal expansion and vibrational spectroscopy of ammonium bicarbonate using HRPD.
DOI: 10.21979/n9/fhbr2e/e32dzq
title: 4571_nodes_and_4762_edges_graph.tab
DOI: 10.5286/isis.e.rb1500002
title: PNR Measurement of Spin Pumping in a Metal and an Organic Semiconductor
DOI: 10.5286/isis.e.rb1510161
title: PNR of Magnetic Order in Delta-Doped Topological Insulators

description: We aim at studying proximity effects between a ferromagnetic thin film (either metallic or insulating) and a topological insulator (either undoped, or magnetically homogeneously or delta-doped). For this purpose, we have grown (CrxBi1-x)2Se/Te3 thin films of varying Cr concentration on Al2O3, as well as ferromagnetic FeCo and EuO layers. We have successfully demonstrated the enhancement of magnetic ordering in a topological insulator by ferromagnetic proximity coupling and hope that this study will allow us to further understand the magnetic doping of topological insulators by engineering the doping mechanism. Together with complementary XMCD and SQUID data, we hope to be able to understand and control the FM-TI interface.
DOI: 10.5286/isis.e.rb1510203
title: The coupling of spin and charge correlations in La2-xSrxCuO4

description: Charge density wave (CDW) order has recently been established as a generic feature of  high-temperature cuprate superconductors. It occurs near 1/8 doping and has been observed by x-rays which see it appearing below the pseudogap temperature. CDW order competes with the superconductivity. Some cuprates also show incommensurate spin density order (SDW).  In La2-xSrxCuO4, this occurs for similar dopings as the CDW order. The co-existence of the two types of order suggests that they are microscopically intertwinned and are due to static stripes involving spin and charge modulations. Here will will search to see whether the spin and charge orders are also connected in the dynamics of 1/8 La2-xSrxCuO4. In particular, we will see whether the magnetic excitations are modified as charge correlations develop. The experiment will shed light on the origin of superconductivity in the cuprates.
DOI: 10.5286/isis.e.rb1510342
title: Effect of oxidation on lipid raft formation: a SANS study

description: The separation of particular lipids in cell membranes into liquid ordered and liquid disorder regions is thought to have a major influence of the functioning of membrane proteins. In this proposal we will examine changes to the ordering of lipids following oxidation events. Small angle neutron scattering will be used in combination with contrast variation as a non-invasive method to detect changes to the size of the lipid rafts (microdomains) as lipid vesicles are oxidized in situ. The vesicles will be prepared from a ternary mixture of lipids known to form rafts at low temperatures but not high temperatures, DPPC:DOPC:chol in ratios of 2:2:1 and 1:1:1.
DOI: 10.5286/isis.e.rb1510380
title: Control of chiral magnetic textures in B20 transition metal germanide epilayers

description: In order to realise the technological potential of skyrmion-based spintronics, thin film materials with high ordering temperatures and controlled skyrmion size are needed. The canonical B20 FeGe magnetically orders below about 280 K and and has a skyrmion size of ~90 nm, set by the pitch of the spin helix in the helimagnetic ground state. It is known that substituting Mn onto the Fe site (reducing the electron density) causes a change in sign of the DMI at which a divergence of the helix pitch takes place, but doping on the Co site is unexplored. In our previous beamtime we measured two Fe(1-x)Co(x)Ge epilayers, with x = 0.3 and 0.6 and saw tantalising hints of another unexpected divergence at x = 0.6. Here we propose an experiment where we will look more closely in this composition range in order to confirm the presence of this divergence and map its features more clearly.
DOI: 10.5286/isis.e.rb1510573
title: Folated derivatized nanoemulsions for the treatment of cancer

description: Nanoemulsions (NE) i.e. nanoparticles containing a fluid lipid or oil dispersed in water and stabilized by a surfactant particles have attracted considerable attention as vehicles for the delivery of poorly-water soluble drugs. We have recently developed a series of novel nanoemulsions containing soybean oil as the disperse phase and stabilised by the non-ionic surfactant, oleyl polyoxethylene (10) ether. Significantly a proportion of the surfactant molecules contain a folic acid receptor targeting group on the terminal hydroxyl to enable cellular targeting of the nanoemulsions. The proposed SANS study will determine the effect of the presence of the targeting moiety on the properties of the nanoparticles. The insight provided by the study should provide a better understanding of the potential of NE as vehicles for drug delivery.
DOI: 10.5286/isis.e.rb1510575
title: Nanosuspsomicroemulsions: nanosuspension stabilty

description: At Kings College London we have recently developed a novel combination formulation, a nanosuspsomicroemulsion (NSME), comprising of a microemulsion (ME) containing one drug and polymer and/or surfactant coated nanoparticles (NS) of a second drug to allow co-administration of two poorly water soluble drugs. The aim of the study is to use SANS in combination with contrast variation to determine the size (in situ) of drug NS contained in the NSME. By contrast matching the ME droplets it will be possible to mask their presence enabling the size and stability of the NP to be determined in situ, something not readily possible by any other technique. The results of the study will be invaluable in establishing whether it is possible to use this novel formulation to deliver combination drug therapy.
DOI: 10.5286/isis.e.rb1510619
title: CEF investigation to clarify dual Kondo temperature in a Ce clathrate

description: Type-I clathrates are of active interest for thermoelectric applications at temperatures above room temperature. This is mostly due to rattling modes of the guest atoms in these cage compounds which lead, by interaction with the acoustic phonon modes, to very low lattice thermal conductivities. Recently, the first Cerium-containing clathrate, CeBa7Au6Si40, was discovered by our group. At 600 K, it shows a 100% enhancement of the thermoelectric figure of merit ZT over a Ce-free reference compound. As mechanism of this extraordinary effect, a Kondo temperature TK of several 100 K was proposed to exist in this material, in addition to a low-temperature Kondo scale of about 1 K.  We propose here to carry out inelastic neutron scattering measurements on CeBa7Au6Si40 to test the proposed claim of a dual Kondo temperature by measuring crystal field excitations.
DOI: 10.5286/isis.e.rb1510644
title: The Structure of Olefin  Methanol Solutions

description: We request beam-time for high-resolution neutron diffraction in conjunction with hydrogen/deuterium isotopic labelling and EPSR analysis to probe the detailed 3-dimensional spatial and orientational structure of methanol-olefin (1-pentene and 1-hexene) mixtures above the Upper Critical Solution Temperature (UCST). In addition to providing decisive information regarding the nature of the proposed -OH¿¿¿π hydrogen bonding structure, the use of NIMROD will also allow us to investigate the nature of mixing/demixing of solvent and solute above the UCST. For each olefin 2 compositions will be studied at 25 and 75 mol % solute with isotopic labelling of protons on both solvent (methyl and hydroxyl groups) and solute. For each sample we propose 8 isotopic compositions in total.
DOI: 10.5286/isis.e.rb1520360
title: Slow magnetic fluctuations and superconductivity in CeRhIn5 at ambient pressures:

description: CeRhIn5 is an antiferromagnetic itinerant magnet which illustrates a temperature and pressure interplay between antiferromagnetism and superconductivity.  Recently, it has been demonstrated that this system displays both well defined spin-wave excitations yet also a decay of these indicating a breakdown of a single quasiparticle description of this system.  We propose a muon study to investigate the low-energy magnetic fluctuations to investigate the response to superconductivity, which is currently controversial and also to search for slow magnetic fluctuations associated with the neutron data taken on the THz timescale.
DOI: 10.5286/isis.e.rb1610106
title: Apatite-type Oxides for Energy Applications:  Symmetry Distortion Mode Analysis of 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 4 days of HRPD beamtime for high resolution neuton diffraction experiments on a series of apatite materials, which adopt triclinic, hexagonal and monoclinic structures.
DOI: 10.5286/isis.e.rb1610122
title: Modelling of surfactant phase behaviour versus concentration below ambient temperatures

description: We wish to understand how the concentration of surfactant mixtures in solution affects adsorption at lower temperatures; in particular, we wish to see how the composition of the adsorped layer changes. Previous experiments have shown large changes in composition when the temperature was decreased from 25oC to 10oC, but little change in the cmc - the bulk properties appear to be largely unaffected by the same temperature changes. The surface tension was also invariant when the temperature was dropped, implying little change in surface activity (i.e. any changes are compositional only). By varying the concentration and observing how the composition of the adsorped layer changes, we hope to further understand what components of the surfactant molecules are affected most by temperature changes and hence what drives adsorption in cold water solutions.
DOI: 10.5286/isis.e.rb1610136
title: A muSR Investigation of the Magnetic Ground State and Spin Dynamics in the Triangular Antiferromagnet TbInO3

description: In a typical magnetic material the interactions between neighbouring magnetic moments will tend to lead to their ordered alignment throughout the entire structure as it is cooled down. In a special class of magnetic materials, known as geometrically frustrated magnets, the particular arrangement of magnetic moments within the structure prevents typical long range order from occurring. The frustration of the magnetic interactions in a material is important, therefore, as it can induce very unusual magnetic behaviour. TbInO3 is an excellent example of such a material. We have performed a detailed study of TbInO3 through various experimental techniques. Crucially, whether or not the magnetic Tb3+ ions in TbInO3 adopt long rang order not is still unclear. Here we propose to study the magnetic properties of TbInO3 at the lowest temperatures by muon spin relaxation measurements.
DOI: 10.5286/isis.e.rb1610141
title: Single-Crystal Neutron Diffraction Studies of Giant Pentaphosphaferrocene-Based Supramolecules

description: Single crystal neutron diffraction using SXD diffractometer of crystals containing giant pentaphosphaferrocene-based supramolecules. Aims are the localization of the disordered metallocene guest molecule in the spherical host cavity, and localizaton of low-occupied positions of Cu, Ag and halogen atoms in the disordered core of the supramolecule.
DOI: 10.5286/isis.e.rb1610277
title: Superconductivity in tetragonal FeS

description: The possibility of superconductivity in tetragonal FeS has attracted considerable interest because of its similarities to the FeSe superconductor. However, for a long time all efforts made to prepare tetragonal FeS have failed, and it was not known whether tetragonal FeS is metallic or semiconducting.  In 2015, a new synthesis route was identified and FeS was found to be a 5 K superconductor.  Comparison with FeSe demonstrates that the two materials are quite different and the change from sulphur to selenium is associated with some rather subtle changes in physical behaviour.  We propose to measure the superfluid stiffness in this newly discovered superconductor and to use the resulting information to compare with data previously obtained on FeSe.
DOI: 10.5286/isis.e.rb1610332
title: Diffusive character of hydration water on protein surface by examining perdueterated cytochrome P450 powders

description: Water is crucial for the functioning of proteins. There has been substantial work to study the effect of water on protein dynamics, structure and function. However, how protein structure affects the dynamics of water, especially the diffusive character of water, is not thoroughly explored. Our earlier work on perdeuterated GFP showed that the hydration water molecules perform a sub-diffusive motion, which is quantitatively confirmed by our molecular dynamics simulation. However, our further molecular dynamics simulation found that the sub-diffusive nature of hydration water and the detailed diffusion rule are universal and independent on the structure of the associated protein. To support this simulation-derived conclusion, we require dynamic neutron scattering data on another perdeuterated protein, which is P450 as proposed here, and it is the essential goal of this proposal.