cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1820078
title: Spinon spectrum determination of a spin 1/2 Heisenberg antiferromagnetic  C12D14CuN4O5

description: Entanglement refers to the phenomenon of two quantum mechanical objects correlated with each other at large distances and proposed to affect quantum criticality, the critical point of a quantum phase transition and governed by non-thermal control parameters such as magnetic field H.  C12D14CuN4O5, a good representation of a one dimensional spin ½ Heisenberg antiferromagnetic with an exchange coupling constant J/kB ~ 3.2 K,  has been shown to be quantum critical with respect to H. Measurement of magnetic susceptibility showed a variation of J/kB across the critical field, and hence, a non-monotonic field variation of entanglement. Such a field dependent variation of J/kB has not been previously observed. We want to investigate the spinon spectrum by inelastic neutron scattering experiments at different temperatures down to 100 mK as well as estimate J/kB at H = 0 using LET spectrometer.
DOI: 10.5286/isis.e.rb1820209
title: Magnetic ground state of the breathing pyrochlore Ba3Yb2Zn5O11

description: "Breathing pyrochlores" are a new class of material that contain sublattices of corner sharing tetrahedra, where the the sizes of the tetrahedra differ on the different sublattices. The recently synthesised Ba3Yb2Zn5O11 has been reported to be such a geometrically frustrated pyrochlore, in which the Yb ions adopt a pseudo-spin-1/2 ground state. The measured negative Curie-Weiss temperature indicates significant antiferromagnetic exchange couplings. However, no long range order has been observed to sub-Kelvin temperatures, and a proposed theoretical model predicts the emergence of a quantum spin ice state in breathing pyrochlores. We propose to investigate and characterise the magnetic ground state of this material using positive muons as local magnetic probes, utilising their sensitivity to long range order formation and the dynamics of the magnetic moments.
DOI: 10.5286/isis.e.rb1820298
title: Understanding the structure of sodium laureth sulfate and NaCl mixtures in water

description: The objective of this research is to understand the detailed structure of water-surfactant solutions as a function of concentration of salt.  This is important as these materials form the main components of personal care products and this fundamental understanding will provide the basis of new formulations.
DOI: 10.5286/isis.e.rb1820466
title: Magnetic fluctuations and ordering in two-dimensional and ferromagnetic Cr2Ge2Te6:

description: The proposal requests time to measure the magnetic fluctuations in a 2 dimensional ferromagnet where the dimensionality is set by weak van der Waals forces.  We have previously performed measurements at low energies on MACS (NIST) which indicate that the fluctuations extend to much higher energies than possible on MACS and also the possibility of the existence of magnon decay.  MAPS is requested given the low-angles required and also the better momentum resolution over MERLIN.  The results will be compared with STM measurements currently being performed at St. Andrews on this material.
DOI: 10.21227/gh6y-kt46
title: A DATA-SELECTIVE LS SOLUTION TO TDOA-BASED SOURCE LOCALIZATION

description: This data-set was used for the localization of an emitter based on Time Difference of Arrival (TDoA).The classical least-squares (LS) algorithm, with a limited number of TDoA measurements, has been utilized for obtaining a closed-form solution to the source localization problem.An extension of the classical LS algorithm has been employed in an attempt to improve the precision of the localization technique by using a larger set of TDoA estimates.Considering all TDoA values can eventually degrade the accuracy of the localization method due to the presence of heavily noisy measurements.The ICASSP 2019 paper entitled " A DATA-SELECTIVE LS SOLUTION TO TDOA-BASED SOURCE LOCALIZATION", by employing a data-selective approach, proposes a closed-form LS solution that disregards bad measurements.To this end, two distinct objective functions are used: one to obtain a solution and a second one to test that particular solution among all possible ones within a subset of measurements.This data-set corresponds to all recordings of the real-life experiment carried out in this paper. From processing these recordings, we observe the superior performance of the proposed algorithm in the source localization problem.
DOI: 10.5286/isis.e.rb1510160
title: Investigating Nano-segregation and Structuring in Ionic Liquid Mixtures using SANS

description: It is proposed to use small-angle neutron scattering (SANS) to investigate in detail the binary phase diagram between 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][Tf2N]) and 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C12MIM][Tf2N]) in order to provide information on the organisation of one ionic liquid within the other. The work will be carried out by preparing one of the ionic liquids in perdeuterated form and taking advantage of the contrast variation that this offers. The proposal is made following preliminary Xpress experiments on Sans2d and is complementary to an application for reflectivity measurements submitted this round.  The results will be complemented by those from laboratory experiments using surface tension and viscosity measurements to provide a very detailed picture of the binary behaviour of this system.
DOI: 10.5286/isis.e.rb1510180
title: Simultaneous Microwave Dielectric Spectroscopy and Neutron Diffraction to Monitor Ammonia Uptake in the CPO-27 Metal-Organic Frameworks

description: With appropriate storage materials, ammonia has great potential as a fuel. We propose to use a novel piece of equipment, which combines microwave and neutron diffraction analysis, to examine the uptake of ammonia by microporous metal-organic frameworks. This unique analytical combination will allow us to study both the structural changes of the materials and the dynamics of ammonia sorption/desorption, which will shed great insight onto desirable design features to improve storage capacities and refueling speeds.
DOI: 10.5286/isis.e.rb1510557
title: Investigating liposome sensitivity towards phospholipases for applications in diagnostics and drug delivery

description: Liposomes are lipid-based, water-filled vesicles with wide-ranging applications in diagnostics and drug delivery. Phospholipases (PLs) are enzymes that cleave specific bonds in phospholipids. Reactions of PLs with liposomes are of huge interest on both an application led and basic research level. PLC and D are known markers for many diseases, but little is known about their effect on liposomes. We propose a series of kinetic experiments measuring five liposome formulations of interest as they are incubated with four PLs. The invaluable data provided on the effect of PLs on membrane bilayer thickness and permeability/fluidity, liposome stability and size distribution, answer an interesting basic research question and are vital to develop much-needed diagnostic and screening assays/drug delivery vectors for e.g. tuberculosis, cancers, Alzheimer's disease, atherosclerosis and depression.
DOI: 10.5286/isis.e.rb1520014
title: Structural and magnetic orders in Ga-V oxide spinels

description: In certain materials, notably with the spinel structure, orbital ordering can result in the formation of a ground state with electrons delocalising between small numbers of adjacent cations, called ?orbital molecules?. Two new spinels, GaV2O4 (a = 8.3130(5) Å) and Li0.5Ga0.5V2O4 (a = 8.3129(1) Å), have recently been synthesised by high temperature solid-state reactions as candidate orbital molecule materials. GaV2O4 is paramagnetic down to 4 K, but a sharp magnetic ordering transition is observed at 15 K for Li0.5Ga0.5V2O4.We request 2 days on HRPD to study the crystal and magnetic structures of GaV2O4 and Li0.5Ga0.5V2O4, over the temperature range 4-300 K.  Neutrons are required to refine cation occupancies and observe magnetic order, and the high resolution of HRPD is needed to observe any subtle superstructures associated with orbital/spin orders.
DOI: 10.5286/isis.e.rb1520091
title: A high-temperature neutron powder determination of the phase transition and crystal structures of Cu2ZnSnS4

description: Cu2ZnSnS4 (CZTS) is a solar cell material of great interest. However the material when fabricated, although of high symmetry, contains substantial defect concentration and a high degree of atomic mixing on different crystallographic sites. A lack of knowledge regarding the structure is currently hampering progress on this material. X-ray measurements have shown anion displacement changes begin around 420 K with a phase transition between the low-temperature kesterite structure and a high-temperature sphalerite structure at 1149 K. In the region 1136-1161 K a two-phase region occurs with both phases coexisting around the first order phase transition. We propose to undertake high-resolution neutron powder diffraction study to fully characterise the material from 4 K to 1200 K using HRPD.
DOI: 10.5286/isis.e.rb1520128
title: Metal Distributions in TiCoSb and (Ti1-xVx)Co1-yFey(Sb1-zSnz) half-Heusler Thermoelectrics: unexpected n-type conduction.

description: TiCoSb based half-Heusler compositions are of interest as p-type elements in thermoelectric waste heat recovery. We have found unexpected n-type behaviour in the title materials. We request one day of beamtime on the Polaris instrument to investigate the metal distributions over the available crystallographic sites. This information is needed to explain the observed n-type conduction.
DOI: 10.5286/isis.e.rb1520217
title: Chemical control of structures and properties of cobalt oxide chalcogenides

description: The evolution of the crystal structures and magnetic ordering of layered cobalt oxide chalcogenides will be probed as a function of composition. The systems Sr2CoO2Cu2-zSe2 and Sr2CoO2Ag2-zSe2 are obtained by the removal of some of the copper or silver from the parent materials (with z = 0) using an iodine solution. This process is topotactic and conserves the basic structure. The parent materials show long range antiferromagnetic ordering of the Co sublattice with large orbital enhancements to the moments and evidence for competing magnetic structures.  Variable temperature high resolution neutron diffraction will probe of the effect of the chemical oxidation on the long range magnetic order and the competition between magnetic ground states and this will give insight into the fundamental magnetic, electronic and transport properties of these materials.
DOI: 10.5286/isis.e.rb1520223
title: Distribution of Copper in TiNiCuySn (0 &lt; y &lt; 0.25) Half-Heusler Nanocomposites

description: Metal-rich TiNiCuySn Half-Heusler nanocomposites have promising power factors and may find application in thermoelectric waste heat recovery. The aim of the experiment is to determine the distribution of the excess copper, which is either contained within the TiNiSn matrix or fully segregated into a distinct TiNiCuSn phase. Laboratory X-ray powder diffraction reveals substantial changes in the copper distribution when comparing cold-pressed and hot-pressed samples but cannot be used to determined accurate compositions due to the similar scattering strength of Ti, Ni and Cu. Neutron powder diffraction does provide good scattering contrast and is needed to determine accurate experimental compositions for the matrix and the fully segregated phase.
DOI: 10.5286/isis.e.rb1520464
title: QENS analysis of industrially relevant small pore zeolites

description: NOx emissions from the energy and transport sectors represent a major hazard to human health and this has been the focus of significant industrial and academic research.  One of the important processes in the armoury available for emissions control from vehicles, large and small, power stations, ships, trains and non-road machinery is the selective catalytic reduction reaction (SCR), in which a reductant such as ammonia, urea or hydrocarbon fuel, is injected into the exhaust to reduce the NO and NO2 (NOx) to harmless nitrogen.  Copper supported on a zeolite have proven to be extremely active for SCR, and also demonstrate excellent long term stability, and are therefore often the prime choice for use in the catalytic SCR system. For these initial experiments we wish to investigate how the presence of copper and the shape of the zeolite modifies the diffusion of ammonia.
DOI: 10.5286/isis.e.rb1820337
title: Direct observation of sodium ionic conduction in Na3PS4-based solid electrolytes

description: All solid-state sodium ion batteries are potential low-cost alternatives to lithium ion batteries, especially for static and large-scale energy storage systems. The shift from liquid to solid electrolytes also promises major gains in battery safety. The critical challenge for all solid-state batteries is the lack of high conductivity electrolytes. In order to improve existing materials and develop new ones, we require not only a detailed knowledge of the structural properties of these materials, but also of the conduction mechanisms at the atomic scale. The proposed experiment aims to investigate the atomic scale conduction mechanisms by means of quasielastic neutron scattering in promising solid-state electrolytes based on Na3PS4 and elucidate the influence different doping strategies (i.e. the introduction of Na vacancies vs. Na interstitials) onto the Na diffusion process.
DOI: 10.5286/isis.e.rb1820508
title: Continuation: Magnetic Excitations in doped Ca3Ru2O7 - Investigating the role of SOC in the 4d-electron ruthenates

description: Ca3Ru2O7 plays host to a complex interplay between equivalent spin-orbit coupling (SOC) and electron correlation energies that foster exotic physics and an extreme sensitivity to external perturbation. Even with a nominal x=0.02 Ti substitution in Ca3Ru2-xTixO7 is enough to push the system from a correlated metallic system into a Mott insulating state, concomitant with a magnetic structural transition. We have performed several experiments on the system and found anti-ferromagnetic spin waves and a non-dispersive excitation at 20meV at the magnetic ordering vector.To investigate this feature closer a high-statistics dataset with a large volume in reciprocal space is required.We propose to perform an INS experiment using the MERLIN spectrometer. It is optimized for highest neuton flux in the regime and its updated electronics will overcome previously encountered saturation effects.
DOI: 10.5286/isis.e.rb1820558
title: In-operando diffusion measurements on an all-solid-state battery cell

description: We propose to use muons to probe the diffusion processes which occur within a battery anode during cycling in an all solid-state battery. Such solid-state battery configurations present safer alternatives to current organic-based liquid electrolyte cells which are flammable and operate within a limited voltage window. However, issues remain with optimising lithium diffusion across the solid electrolyte-electrode interface in all solid-state cells. In operando muon spectorsocpy studies will provide a truly local probe of the lithrium diffusion dynamics in solid-state battery components. This represents the first study of its kind and will ultimately provide the community with a battery cell and protocol for in operando muon measurements for batteries.
DOI: 10.5286/isis.e.rb1910597
title: Using QLCR to Study Stopping Sites in Molecular Solids

description: Muon nuclear quadrupolar level crossing resonance is not a well-known technique, however it is extremely powerful. There is a large interest in probing the muon stopping site and the behaviour of molecular solids where the elusive diamagnetic muonium fraction is present. For this to work you require a nuclei where I&gt;1, and then the resonance field relates to the electric field gradient across the nuclei. QLCR has been performed on nitrogen and this has been successful, we seek to expend this to molecular solids where there are CN groups present, which are isoelectronic to nitrogen. This will present us with a way to not only probe the muon stopping sites and relate this to physical properties.
DOI: 10.5286/isis.e.rb1910612
title: Probing the magnetic ground state in one dimensional magnetic systems Ba3CrS5 and Ba3CrSe5

description: Most of the one dimensional spin chain compounds are antiferromagnetic with a rich magnetic phase diagram due to the magnetic frustration. We have synthesized Ba3CrS5 and Ba3CrSe5, which forming chains of CrS(Se)6 octahedra along c-axis. The magnetic structure, investigated using neutron diffraction study reveals the ferromagnetic arrangement of the Cr3+ moments in the ab-plane, while anti-ferromagnetic coupling of the FM planes along the c-axis. Based on the DFT+U calculation, we have found the band gap is ~0.78 eV. Our recent INS study on Ba3CrS5 shows the signature of short range ordering. Hence, detailed study regarding nature of magnetic ground state of these spin chain compounds, Ba3CrS5 and Ba3CrSe5 is important to get insight of physics behind the various interesting properties of these systems and for this investigation muon spin relaxation is a very useful tool.
DOI: 10.5286/isis.e.rb1510025
title: Improper ferroelectricity in hexagonal tungsten bronzes

description: We address the detailed atomistic mechanism of ferroelectricity in a new family of  oxides typified by the composition CsNbW2O9. Contrary to the mechanism in most ferroelectrics, the characteristic electrical polarisation is not caused spontaneously by polar displacements of ionic species in the crystal, but arises as a secondary consequence of a non-polar lattice instability (so-called 'improper' ferroelectricity). These compounds therefore have something in common with the well-known improper ferroelectric YMnO3, but the similarity is based on symmetry considerations (they are both hexagonal crystals) rather than any direct chemical or structural similarity. We propose to study the detailed nature of this new family of improper ferroelectrics, particularly the transition into the ferroelectric state and the crystallographic features that drive it, for which HRPD is essential.
DOI: 10.5286/isis.e.rb1520008
title: A new way to form reversed micelles in supercritical CO2

description: Spherical reverse micelles have been formed previously in water-in-sc-carbon dioxide (w/c) microemulsions through the use of a special partially fluorinated hybrid surfactant3 (figure 1, b-d). The inclusion of hydrotropic salts (figure 1-a) in these systems shows promise for increasing the system viscosity, through elongation of spherical reverse micelles to form ellipsoidal and reversed worm-like micelles (RWLMs)4,5. This research has received external publicity through the UK government agency UK trade and Investment (UKTI)7 and is supported by an STFC funded studentship ST/L502613/1 - ?Controlling fluid properties of dense CO2? and the G8 Research Councils Initiative on Multilateral Research Funding - G8-2012 - EP/K020676/1.
DOI: 10.5286/isis.e.rb1520121
title: Inelastic neutron scattering study on quaternary borocarbides PrPt2B2C and PrPd2B2C

description: The  borocarbides PrPt2B2C and PrPd2B2C forming in the tetragonal structure do not show any long range magnetic order down to 0.5 K. PrPt2B2C shows a superconducting transition at Tc =6 K whereas PrPd2B2C behaves like a Van?Vleck paramagnet.  The heat capacity data of both show broad Schottky type anomaly due to the presence of crystal electric field (CEF). An analysis of heat capacity data reveals a possible CEF split singlet ground state in these compounds. The CEF wave functions play an important role in governing the magnetic and superconducting properties, therefore it would be of interest to investigate the CEF excitations in these compounds using inelastic neutron scattering technique for a better insight to the magnetic/superconducting ground state and absence of magnetic ordering in these compounds. We therefore propose to carry out INS study on these compounds using MARI.
DOI: 10.5286/isis.e.rb1520302
title: Towards designing multiferroic materials with predictable transition temperatures

description: BiFeO3 continues to be the most widely studing multiferroic material as a result of its room temperature magnetic and electric ordering. However, many barriers limit the commercial viability of BiFeO3 including high leakage currents and weak magnetoelectric coupling. More recently researchers have looked to doping BiFeO3 with rare earths such as La3+ or Nd3+. Whilst A-site cation size effects and rare earth polarizability have been shown to be important it has not been possible to generate a global understanding of these materials which would allow for predictable design. We have synthesised materials which have allowed us to decouple these two effects allowing us to probe the structure-property effects of A-site doping in BiFeO3. We propose to extend this lab based study to investgate cation displacement and octahedral rotation by neutron diffraction giving an enhanced understanding.
DOI: 10.5286/isis.e.rb1520313
title: Part B: Binding behaviour of PAMAMs G5 and G4.5 to zwitterionic and anionic lipid bilayers

description: Polymers are commonly used in drug delivery to create dosage forms that enable delivery of the active ingredient to the site of action within the body. Towards controlled drug delivery polymers enable the development of systems that help to minimise side effects. There are a variety of ways in which polymers can interact with cell membranes, via specific receptors and also via disruption of the lipid membrane itself. We have been investigating the role of different properties of polymers on their ability to interact with lipid membranes. PAMAM is a highly branched polymer with either cationic (G5) or anionic (G4.5) end groups. In this proposal we ask for neutron reflectometry INTER beam time to investigate the interfacial structure of lipid layers in the presence of PAMAM G4.5 and G5.
DOI: 10.5286/isis.e.rb1520335
title: Magnetic and Quadrupolar Excitations in 5d based Double Perovskites Ba2BOsO6 (B=Na,Ca)

description: Like the well known perovskites, the double perovskites A2BB'O6 form an enormous family of compounds exhibiting a wealth of phenomena ranging from magnetic long range order, multiferroicity, spin liquid behaviour or ferroelectricity. Recently, the vital role of spin orbit coupling in determining their ground state properties has been realised, particularly in the higher 4d and 5d transition metal systems. We propose an inelastic neutron scattering investigation of the excitation spectrum in two model osmium based 5d1 and 5d2 double perovskites, model systems for which comprehensive theoretical predictions have been made, but where detailed Q resolved studies of the dispersion are lacking to date
DOI: 10.5286/isis.e.rb1520368
title: Test for clustering in dilute CoxMg1-xO (x=0.03):

description: We have been pursuing a study of the magnetic fluctuations in CoO involving a single crystal experiment on MERLIN.  To understand the complex magnetic hamiltonian involving spin-orbit, structural distortion terms, and spin exchange, we have in parallel been studying dilute samples of MgO doped with a small amount of Cobalt.  As shown previously in a number of studies, these dilute compounds can be understood in terms of comparatively simple dimer physics.  This is a large simplification to the Hamiltonian and provides an important constraint in the model to understand the magnetic excitations in pure CoO.  One concerns is that our dilute samples have a large amount of clustering of Cobalt sites.  We propose to test this and have made a large homogeneous dilute sample based on the sol-gel technique.  We request 1 day on IRIS and 1 day on MARI to compare these samples.