cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1620190
title: Crystal Field Study of the Rare Earth Pyrochlores Sm2Hf2O7, Sm2Zr2O7 and Dy2Ti2O7

description: Rare earth pyrochlores R2T2O7 have attracted attention because of the wide range of interesting and unusual magnetic behavior they present, in particular the observation of monopoles in the spin-ice compounds Dy2Ti2O7 and Ho2Ti2O7 has motivated the search for new pyrochlore spin-ice/spin-liquid candidates. The rare earth hafnates and zirconate pyrochlores have not been explored and are potential candidates for exotic physics. The goal of this experiment is the precise determination of the crystal field levels of the rare earth ions in Sm2Hf2O7, Sm2Zr2O7 and Dy2Ti2O7 by performing powder inelastic neutron scattering on the Merlin spectrometer. This will provide information for understanding the magnetic anisotropies and single ion ground states which will give crucial insight into the nature of the competing interactions in them and the type of physical phenomena they will demonstrate.
DOI: 10.5286/isis.e.rb1620240
title: Investigating the diffusion of cyclic oximes in hierarchically-porous catalysts for the Beckmann rearrangement

description: Caprolactam (CL) is a high-value chemical precursor to nylon-6. On an industrial scale an aggressive liquid-acid catalyst is used to transform C6-oxime to CL. Due to environmental issues and low-selectivities, there is a necessity to find a solid-acid alternative. Silicon-containing aluminophosphates (SAPOs) have been successful due to their tunability, high yields, and recyclability. However, where the small channels of microporous SAPOs restrict substrate movement and increase pore blockage, hierarchically-porous (HP) SAPOs (containing larger mesopores) exhibit longer lifetimes and improved yields. Previous QENS results were encouraging in picking up differences in diffusion modes within microporous SAPOs.  This experiment is targeted at solely hierarchical structures to probe diffusion, in hitherto unexplored porous structures, containing interconnecting micropores and mesopore
DOI: 10.5286/isis.e.rb1620272
title: High Energy Spin Fluctuations in YFe2Ge2

description: The recently discovered superconductor YFe2Ge2 (Tc about 1.8K) has the same crystal structure as 122 iron-based superconductors, with no static magnetic order be reported. However, our recent triple-axis experiment revealed strong spin fluctuations at Q=(1,0,1), corresponding to a stripe antiferromagnetic correlation consistent with in the 122 systems. Thus, there comes a contradiction between the similarity to 122 systems and the rather low Tc in YFe2Ge2. In order to have further understanding of the superconducting mechanism of this compound, we propose an experiment on the high energy spin fluctuations in YFe2Ge2, which will enable us to determine the effective Hamiltonian and to make a direct comparison with the 122 iron-based superconductors. Our experiment will shed some lights on the mechanism of pairing and the origin of low Tc. We request a 7 days' beam time for MAPS.
DOI: 10.5286/isis.e.rb1620479
title: Linking solvent structure to materials synthesis: Choline Chloride:Urea-Water and Choline Chloride:Malonic Acid

description: Deep Eutectic Solvents (DES) are formed by complexing appropriate organic salts and neutral hydrogen bond donor species to produce chemically tuneable, low volatility liquids that are generally environmentally benign. In our recent NIMROD study of a DES - water mixture with demonstrated utility for the formation of novel ceria nanostructures, we found that a hypothesized phase separation, based on NMR results, does not occur in the mixture. Here we propose to expand the study of the intermolecular liquid structure to mixtures with higher water content to allow us to complete our understanding of the structural phase space that governs the reaction media properties. As a second component of this proposal we would also like to characterise the intermolecular structure of the DES based on choline chloride and malonic acic.
DOI: 10.5286/isis.e.rb1700056
title: Determining the Electromechanical Response Mechanism of Nanostructured Ionic Block Co-polymers

description: One of the rapidly developing frontiers in research is focused on the design of materials that have targeted functionalities and tunable responses to external stimuli. A chief obstacle to achieving this capability is the lack of a fundamental understanding of how chemical structure and morphology give rise to macromolecular properties. Our research explores how polymer structure, counterion species, and film morphology affects the electromechanical response of ionic block copolymers when exposed to external electric fields using neutron reflectometry. The study proposed here focuses on understanding how these factors drive the electrostatic and mechanical stresses that result in material deformation.
DOI: 10.5286/isis.e.rb1710009
title: Polymorphism of metastable multiferroic perovskites in the BiFe1-xScxO3 system

description: Metastable multiferroic perovskites of the BiFe1-xScxO3 system, stabilised by high-pressure and high-temperature synthesis, demonstrate irreversible phase transformations upon heating/cooling thermal cycling. This allows the compositions in the range of 0.3x1 to be obtained in different polar/antipolar polymorphs providing a unique opportunity to explore a structure-properties relationship. The proposal aims to study the crystal and magnetic structures of two different polymorphs of the compositions with x=0.3 and 0.7. The as-prepared samples crystalize into orthorhombic and monoclinic modifications, respectively, which irreversibly transform to a novel perovskite phases above 500K.
DOI: 10.5286/isis.e.rb1710074
title: Low dimensional networks under pressure. In-situ diffraction measurements of carbonate glasses.

description: Carbonate liquids are characterised by low temperature and low viscosity and play an important role in molten carbonate fuel cells, battery electrolytes and, surprisingly, in volcanic processes. Indeed they are important agents of element transfer in the deep Earth interior. Despite their unique role determined by structure-related properties little is known about the carbonate liquid structure. The aim of this work is to determine what happens to the carbonate chains when pressure is applied. We have recently completed an experiment on carbonate glasses at 3.3 and 8.5GPa. Ultrasonic measurements suggest a sudden change in the sound velocity in this region and in this proposal we will further explore this regime where structures change most by collected diffraction data for a pressure point at 6GPa. This will be augmented by simulation and NMR measurements.
DOI: 10.5286/isis.e.rb1710093
title: Sequential adsorption of atherosclerotic lipoproteins to study the protective role of high density lipoproteins

description: Atherosclerosis is a major contributor to global morbidity and mortality with 31 % of all deaths in 2008 linked to cardiovascular disease. The development of the disease has been linked to the cholesterol transport system. Uptake, transport and deposition of atherogenic cholesterol esters and triglycerides is facilitated by lipoprotein particles in the blood stream. High (HDL) and low (LDL) density lipoproteins are aggregates of lipophilic cholesterol esters and triglycerides encapsulated by a lipid monolayer and apolipoproteins. HDL has been shown to have a protective effect on the body.  In this work we aim to study the effect of pre-coating lipid bilayers with atheroprotective HDL lipoprotein particles on LDL exchange mechanisms using neutron reflection which is especially sensitive to the adsorption, exchange and uptake of lipids from bilayers.
DOI: 10.5286/isis.e.rb1710106
title: Low energy inelastic neutron studies in Ni-Mn-Sn based shape memory alloy

description: The composition Ni2.04Mn1.4Sn0.56 belongs to the group of metamagnetic shape memory alloys and it shows multiple magnetic phases as a function of temperature. In a recent muon spin rotation experiment on EMU at ISIS, these multiple magnetic transitions are beautifully depicted and it clears out some of the doubts regarding the nature of different magnetic phases. The sample shows paramagnetic behavior between two ferromagnetic phases and has a spin glass like ground state. Our main aim is to study the magenteic excitations by inelastic neutron scattering experiment in two different ferromagnetic phases as well as in the intermediate paramagnetic phase and in the glassy ground state. The possible spin excitations in this system is likely to be in the low energy region and for that we would like to propose a low energy (below 3 meV) inelastic neutron scattering experiment on OSIRIS.
DOI: 10.5286/isis.e.rb1710417
title: Low temperature neutron diffraction of Sm2Ti2O7 pyrochlore compound

description: Topological phases of matter became scientific highlights during the 70's and magnetic frustration is one of the mechanisms that is believed to drive systems to one of that many possible exotic phases. We propose here to carry out measurements on a promissing candidate, the poorly studied pyrochlore Sm2Ti2O7. Because of the Sm extremelly small single ion mangnetic moment, one may expect that magnetism is higly supressed in this pyrochlore. Surprisingly, a sharp and strong phase transition appearing in heat capacity at 350 mK may indicate that samarium titanate has more to show. Our proposal here is to perform polarised and unpolarised neutron diffraction to identify this unknown low temperature phase.
DOI: 10.5286/isis.e.rb1500000
title: Correlations between magnetic order and anomalous polarization changes in pyroelectric materials
DOI: 10.5286/isis.e.rb1510005
title: Multiferroic (Ferroelastic/Magnetic) Phase Transitions in KMnF3

description: KMnF3 perovskite undergoes 3 structural, and two magnetic phase transitions on cooling from 300 K to 2 K. Above 185 K the compound is in the aristotype structure, on cooling below 185 K it undergoes a weakly first order zone boundary phase transition to a structure in space group I4/mcm with Glazer symbol a0a0c-. At the Neel temperature (87 K) it undergoes a second weakly first order transition to an as yet uncharacterised phase, probably space group Cmcm. At 82 K it undergoes a second magnetic/structural transition to another uncharacterised phase, probably in space group Pnma. We propose to carry out a full structural and magnetic characterisation of the 4 phases of KMnF3 including the evolution of the spontaneous strains and the nature of the phase coexistence in the first order transitions on heating and cooling.
DOI: 10.5286/isis.e.rb1510029
title: SOLVENT-MATCHING SANS ON COMPLEXES FORMED BETWEEN DNA AND SHORT AMPHIPHILIC PEPTIDES

description: We will perform SANS investigations on complexes formed between peptide amphiphiles (PAs) and the plasmid DNA pEGFP-N1. Previous SAXS data have shown that our PAs form nanoscopic fibrils or layered structures, thus potentially able to host DNA. We propose solvent matching experiments where D2O/H2O ratio will be varied to separately match the contrast of PAs and DNA. Our data will be combined with cell assays following transfection with the peptide/plasmid complexes to determine a relationship between structure and delivery.
DOI: 10.5286/isis.e.rb1510126
title: The Active Site in Iron Molybdate Catalysts for Selective Methanol Oxidation

description: Formaldehyde is an industrially important chemical (world production 32 million tonnes in 2006) currently made from methanol using an iron molybdate catalyst. Reaction occurs at the surface of these particles, but surface sites are not represented by the bulk. Recent work, using molybdenum oxide support on iron oxide shows that the molydbdenum segregates at the surface and is present in the catalytically active phase. Optical spectroscopy of methanol adsorbed on these catalysts has given valuable information regarding the reaction mechanism. Unfortunately, under higher temperature conditions the catalysts become black and absorb light strongly, preventing this measurement being made. We aim to use inelastic neutron scattering to provide analogous vibrational speactra and characterise the reaction intermediates on these black samples.
DOI: 10.5286/isis.e.rb1510155
title: Time Reversal Symmetry Breaking in Non-Centrosymmetric Superconductor NbOs

description: There has recently been a great deal of interest in noncentrosymmetric superconductors (NCS) due to the complex nature of their superconducting properties. The lack of inversion symmetry in these materials induces an antisymmetric spin-orbit coupling which can lift the degeneracy of the conduction band electrons and may cause the superconducting pair wave function to contain a mixture of singlet-triplet spin states. This mixed pairing can led noncentrosymmetric superconductors to display significantly different properties of that of conventional superconducting systems
DOI: 10.5286/isis.e.rb1510238
title: Neutron Diffraction Residual Strain Measurements of Plasma Sprayed Solid Oxide Fuel Cells

description: Manufacturing of Solid Oxide Fuel Cells (SOFC) using thermal spray technology is one of the most economical and technologically advanced approaches for energy applications. High cooling rates during thermal spray deposition process however impart residual stress in the layered SOFC materials and hence influence the durability and efficiency of the cell. The characterisation of this residual train is therefore critical in optimising the materials and coating process parameters for future generation SOFC. Neutron diffraction due to its high beam penetration, unlike other measurement techniques, offers the opportunity to non-destructively measure the through thickness stress profile in the SOFC assembly. The objective of this proposal is to use neutron scattering (ENGIN-X) due to high flux and deep penetration to study residual strain in air plasma sprayed (APS) anode coatings used in SOFC.
DOI: 10.5286/isis.e.rb1510318
title: Interaction of deuterated thermo-responsive nanogels with lipid multilayers

description: Small gel molecules which can change their properties in response to, for example temperature are important for applications such as drug delivery through the skin.  In order to gain a better understanding of transport of these molecules, we will study their interactions with a model of a skin as a function of temperature.  The outcome of this experiment will be important in designing and optimizing these carriers to deliver medicine efficiently and in a control way.
DOI: 10.5286/isis.e.rb1510419
title: Magnetic contrast reflectometry to resolve transmembrane potential effects on the binding of MinD-MTS to a floating bilayer

description: The division of bacteria is controlled by the binding of proteins to the inner of the two lipid bilayer membranes that separates the inside of the cell from the outside world. This membrane behaves like a capacitor and its properties are thought to vary with the size of the electrical potential that  exists across it. We can construct a flat model for this membrane above a gold-coated silicon block and use the reflection of neutrons from this thin film to probe the details of the structure of the membrane and how this changes with an applied electrical potential and when the anchoring peptide of the cell division protein inserts into the membrane. From this information we hope to understand if the insertion of this protein is controlled by the electrical potential, which can be related to metabolic state of actual bacteria. In the long term this may help to control bacterial infection.
DOI: 10.5286/isis.e.rb1510637
title: D2O Vapour Diffusion at the Air Water Interface

description: A theoretical estimate of the H/D exchange rate for an open trough (e.g. D2O in ambient atmosphere, 50% relative humidity) yields an amount of exchanged liquid of the order of 10^-2 g after 800 minutes for a standard ISIS trough. Recent pilot experiments however show a much greater volume exchange (~10g/800 minutes). We would like to perform a quantitative study of H/D exchange at the air-water interface to determine the rates of exchange of D2O vapour into null-reflecting water for different conditions (surface-to-volume, humidity). Furthermore we intend to study the potential formation of a D2O rich layer at the vapour/liquid interface.We expect that the results will help with future planning of reflectivity experiments involving large are open troughs and will reduce the potential for misinterpretation of data. It will also help further the understanding of this fundamental process.
DOI: 10.5286/isis.e.rb1610165
title: muSR measurements of the superconducting properties of CeCu2Si2

description: CeCu2Si2 was the first heavy fermion superconductor and unlike those previously discovered, which were well explained by BCS theory, CeCu2Si2 is an unconventional superconductor. Like the high temperature superconductors discovered later, the superconducting mechanism is not understood. The structure of the energy gap of superconductors gives information about the pairing mechanism. Surprisingly, recent measurements show the superconducting gap of CeCu2Si2 is fully open, which is not expected for the d-wave pairing which was believed to occur. Muon spectroscopy measurements may help resolve this mystery. We want to perform measurements in zero field to look for spontaneous magnetic fields in the superconducting state, which will allow us to narrow down the possible pairing states. We will also measure the penetration depth using a transverse field which can probe the gap structure.
DOI: 10.5286/isis.e.rb1610531
title: Lipid monolayers at oil/water interfaces at high surface pressure as model biological membrane
DOI: 10.5286/isis.e.rb1620076
title: Neutron diffraction studies of the type of orbital ordering and spin structure associated with wide band SrMn1-xWxO3 (x= 0.1375 and 0.15)

description: Our aim is to investigate the evolution of super-lattice structure (i.e. charge/orbital ordered phase) as well as the associated magnetic structure in SrMn1-xWxO3 (x=0.1375 & 0.15) as a function of temperature (T) (500-4K) by high-resolution neutron powder diffraction. Initial measurements of T dependent XRD (340K-80K) and electrical transport (390K-100K) have been done. Presence of strong CO/OO state at room temperature with compressed pseudo-tetragonal lattice has been observed for SrMn1-xWxO3. The type of lattice distortion associated with CO indicates towards the ordering of dx2-y2 orbitals. It can be confirmed only by investigating the spin structure and accurate oxygen positions analysis in the octahedron. In this proposal,we plan to use the GEM beamline for magnetic and crystal structure investigations.It will help to determine the magnetic structure and type of orbital occupancy.
DOI: 10.5286/isis.e.rb1620210
title: Probing the local magnetic structure and magnetic ground states in strongly spin-orbit coupled Iridates

description: Strong spin-orbit coupling often leads to exotic properties in otherwise a well understood pool of 'paramagnetic' heavy ion oxides.  For a 5d4 system a J=0 total angular momentum ground state should be realised in a jj coupling scheme, which has not been observed till today. This is due to a subtle balance between electronic repulsion, crystal field (CF) and SOC, which makes the J=0 state a fragile one and also because in some cases singlet-triplet excitations of pseudospins may be at play. These excitations give rise to tiny magnetic moments which owing to exchange interactions on geometrically frustrated lattices may give rise to spin-orbital liquid state. We propose to probe with muSR such frustrated 5d4 iridate compounds having variations in the crystal field, based on the local Iridium coordination and overall crystal lattice.
DOI: 10.5286/isis.e.rb1620377
title: Structural distortions at low temperature on the pyrochlore Yb2Ti2O7

description: Magnetic frustration occurs when nearest-neighbor competing interactions cannot be simultaneously satisfied. Pyrochlores, whose crystalline lattices form corner-sharing tetrahedra, provide the perfect architecture for frustrated magnets. The research on pyrochlore compounds is intense and has already demonstrated remarkable features in magnetic materials. Meanwhile, a prominent example in this big family still stands alone. Studies on this Yb2Ti2O7, in many ways, generated more contradictory than clarifying results. After a set of experiments carried out on different samples, its still not possible to determine why this titanate seems to exhibit a striking sample dependence in its physical properties. This work has the objective of clarify some of these inconsistencies.
DOI: 10.5286/isis.e.rb1620421
title: Search for Emergent Photon Excitation in Pr Based Quantum Spin Ice Candidates

description: By introducing transvers terms in the effective spin-1/2 Hamiltonian on the pyrochlore lattice, the quantum spin ice (QSI) state, a special quantum spin liquid whose emergent properties can be described by a U(1)-gauge theory, may be realized. Numerical simulations based on QSI model have predicted the emergence of novel collective excitations such as artificial photons which is gapless with linear dispersion at low energy. However, a convincing realization of the quantum spin ice state in real materials has not been achieved so far, for instance, experimental evidence of gapless photons excitations in these materials has not been found. Our preliminary investigations have indicated that both Pr2Ir2O7 and Pr2Hf2O7 are likely realizations of QSI.  The aim of the proposed experiments is to search for emergent photons excitations in these two samples at LET.
DOI: 10.5286/isis.e.rb1620463
title: Characterisation of the low  temperature phase transition in Pb(CD3COO)2 .3D2O by means of High Resolution Neutron Powder Diffraction

description: We propose to use high resolution neutron powder diffraction for the study of the nuclear structure of Pb(CD3COO)2.3D2O in its low-temperature phase and to characterise with high-precision the evolution of the cell parameters and vibrational frequencies through the transition. The high resolution data will allow us to index uniquely the unit cell of the low temperature phase and solve the structure via ab-initio methods from the powder data. We also propose to use the experiment to commission the HRPD/Raman powder cell.
DOI: 10.5286/isis.e.rb1700030
title: The Structure of Liquid DMAc (Disordered Materials Express)

description: We will use neutron diffraction with isotopic substitution to study Dimethylacetamide (DMAc) in the hope of establishing this amide solvent's structure. Dimethylacetamide is a versatile intermediate with a variety of applications. It is a widely used chemical solvent and has recently become one of few favoured solvents for nanomaterial disperson and dissolution. Though this experiment, we will deduce the structure which governs this solvent's chemical properties. This will allow us to better understand the performance of this important solvent and compare it to other similar commonly-adopted amide solvents.
DOI: 10.5286/isis.e.rb1700045
title: Exotic phase coexistence in magnetic and superconducting LaFe(As1-xPx)(O1-yFy)

description: The proposed 1111 system whose structures are largely underinvestigated exhibits properties with a strong potential for novel properties that complement our knowledge of the heavily investigated 122 system. Of particular interest is the overlapping of the diverse magnetic and superconducting domes and the effects of various dopants at the La, As and O sites in suppressing the magnetic order parameter in favor of enhanced superconductivity. The proposed work should provide important information related to structural symmetries and phase transitions, bond angles and bond lengths that we will ultimately use to design materials with near perfect tetrahedral angle; a condition known to produce materials with the highest superconducting transition temperatures Tc's and to help recovering the magnetic degeneracy in the 122 materials and a phase reentrance into the higher temperature structure.