cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1810109
title: Nature of the new field-induced magnetic phase in ZnCr2Se4

description: ZnCr2Se4 is a magnetically frustrated spinel compound with an incommensurate helical ground state. It has a pyrochloremagnetic sublattice which is formed by Cr3+ (S = 3/2) moments. At low temperatures it displays a helical structurepropagating along the (100) direction. Magnetisation, ultrasound, and neutron-diffraction measurements revealed a yetunidentified phase at higher field. The details of formation of this, so-called spin-nematic, phase remain unclear. The maingoal of this proposal is to investigate the field-dependence of the magnon dispersion, and in particular the behavior of therecently discovered pseudo-Goldstone gap in this material.
DOI: 10.5286/isis.e.rb1810159
title: MuSR study of Na battery electrodes

description: The overall aims of our project is to advance the performance of NIBs in terms of energy and power density by creating a closed-loop approach for materials design, characterisation, modelling and performance. It will involve materials synthesis based on sustainable and upscalable manufacturing technologies and low cost precursors, advanced characterisation of their local structure, electrochemical tests coupled with multiple in operando characterisation tools and theoretical modelling, to fully understand the mechanism and dynamics of Na+ intercalation-deintercalation and establish structure-performance relations. Once the most promising anode materials have been identified, we will assemble and test full cells with well-performing cathodes from parallel research. Using such a circular approach, optimization across the materials synthesis-characterisation-performance will be possible.
DOI: 10.5286/isis.e.rb1810691
title: Ground state selection in quantum spin ice pyrochlores

description: In condensed matter physics, the search for new exotic quantum ground states has become a central theme over the past few years. Among the 3D quantum spin liquid candidates, the rare-earth pyrochlore Yb2Ti2O7 stands out as a very promising one since its lowest Kramers doublet is characterized by XY symmetry and is well separated from the first excited one, giving rise to strong quantum fluctuations with an effective Seff=1/2 moment. Recently, several studies have revealed the dramatic impact of a minute off-stoichiometry x, in Yb2+xTi2-xO7, on its ground state. We now aim at following the evolution of the spin dynamics using inelastic neutron scattering in clean and controlled Yb2(Ti1-xZrx)2O7 samples, going from the pure, x=0, ordered sample through the intermediate region towards the critical, non-magnetic, phase as x increases.
DOI: 10.5286/isis.e.rb1820051
title: Self-assembly in ethyl ester sulfonate surfactants in the presence of electrolyte

description: The methyl ester sulfonate. MES, and ethyl ester sulfonate, EES, are representative of a promising group of anionic surfactants which have the potential for improved performance and biocompatibility / biosustainability. Like LAS, SLES, and MES EES undergoes a transition  from monolayer to multilayer adsorption at the air-water interface in the presence of multivalent counterions. Compared to MES and SLES there are some important differences. Previous studies on MES, SLES and LAS have shown that in order to understand the detailed surface behaviour it is vital to understand the associated solution structure, and we request beam time on SANS2D to investigate the solution structure of EES in the presence of different electrolytes.
DOI: 10.5286/isis.e.rb1820070
title: Towards Active Site Orientation Kinetics in Solution with Quasielastic Neutron Scattering

description: Catalysts are used in virtually all industrial chemical transformations to control reaction pathways by directing the environment around the reactant. Many structural characterisation techniques are therefore used to investigate these systems, although often the dynamic nature of the catalyst is neglected. These motions are well suited to study using the quasielastic neutron scattering (QENS) technique and it may be possible to link these dynamic properties with catalytic activity. The concept of structure-property relationships is common in catalysis, and we hope this experiment will prove the validity of QENS to  provide dynamics-property relationships.
DOI: 10.5286/isis.e.rb1820085
title: Neutron reflection studies on reconstituted wax films interacting with non-ionic surfactant with/without solubilised pesticides

description: From deuterated and hydrogenated wheat waxes we have produced we here propose to use NR to study the structural features of the model wheat wax films formed on the C18 silane hydrophobed surface (self-assembled OTS).  We will then study the adsorption and binding of nonionic C12E6 onto the wax film with and without solublised pesticide DP. By utilising careful isotopic variations, we aim to determine the equilibrated composition and structure of wax, C12E6 and DP across the interface, focusing on understanding the impact of the molecular interaction on the wax film structure in terms of component removal and structural features of the remaining films. The structural information from NR is unique and will well contribute to the understanding of transport of active agrichemicals across wax films. We request 4 days of Surf/Offspec time for completing this experiment.
DOI: 10.5286/isis.e.rb1820245
title: Oxidation of a bilayer of DOPC by aqueous ozone - a chemical, kinetic and mechanistic investigation

description: Mineral aerosol in the atmosphere is a major part of the Earths aerosol budget. Organic films on these aerosols affect the aerosols ability to promote cloud formation and alter its optical properties. Chemical oxidation of this film will cause changes in cloud formation and atmospheric light scattering  both effects in modern climate change. Using neutron reflection to record (1) the oxidation kinetics of a bilayer on a quartz substrate as a proxy for these organic films will allow the atmospheric lifetime to be estimated (and compared to a typical mineral aerosol lifetime of 10 days) and (2) the change in film thickness during oxidation to allow the optical properties of such an aerosol to be calculated with Mie scattering. The oxidant will be the prevalent ozone molecule, contained in cloud water. Its reactivity will be compared to that of OH radicals from recent work.
DOI: 10.5286/isis.e.rb1820283
title: Solid state hydrogen storage in carbon nitride materials for practical applications

description: Existing fossil fuels are on the verge of extinction and  thus in this scenario renewable fuels are need of hour. Hydrogen is potential energy source and can be stored in carbon  materials. We propose to do inelastic neutron diffraction studies  on carbon nitride material using TOSCA. This instrument TOSCA,  combined with volumetric gas sorption experiments, would help to carry out the study for hydrogen storage. The materials graphitic carbon nitride and hybrid of graphene-graphitic carbon nitride were successfully synthesized and depicted good microporosity where we can store molecular hydrogen in solid state. The confinement of hydrogen molecule would be done at liquid nitrogen temperature for practical applications. We initially carried out the studies at room temperature  and pressure, and the material depicted good hydrogen storage potential.
DOI: 10.5286/isis.e.rb1820362
title: Magnon diffusion in the spin Seebeck material magnetite

description: The spin Seebeck effect is a newly discovered phenomenon that if harnessed, could result in a significant improvement of the efficiency of thermoelectric energy generators. SSE devices, however, saturate above a critical thickness limiting their performance. It has been theorised that this saturation length corresponds to the magnon diffusion length. We have recently attempted to measure the magnon lifetimes in Fe3O4 using inelastic neutron scattering using a triple axis spectrometer (IN8 ILL) to try to deduce the magnon diffusion length. Our measurements on IN8 suggest that the magnon dispersion may be different from the literature. To further understand our results from IN8, we propose to use inelastic scattering using the MAPS instrument to obtain a full measurement of the magnon dispersion for Fe3O4. Our results will provide a key test of theory in this rapidly developing field.
DOI: 10.5286/isis.e.rb1820472
title: Is there an incommensurate magnetic resonance in La2-xSrxCuO4?

description: Most optimally-doped high- Tc cuprate superconductors show a magnetic excitation (known as the 'resonance') at q=(pi,pi ) whose intensity increases sharply below Tc. This excitation provides information about the superconducting gap magnitude and symmetry.  It can also be used to probe the pseudogap state above Tc because it appears at the pseudogap temperature T*. Remarkably, such a resonance feature has not yet been established in La2-xSrxCuO4 (LSCO). Here we propose to use the upgraded MAPS to take temperature-dependent measurements of incommensurate spin excitations in LSCO which we believe correspond to the resonance. We propose to look at two samples, optimally doped (p=0.16, Tc=38K, T* ~100 K) and underdoped (p=0.125).
DOI: 10.5286/isis.e.rb1900012
title: Commissioning: Neutron phase-contrast imaging using edge illumination

description: We aim at developing a new methodology to enable neutron phase-contrast imaging with extended sources and white beam. The approach here proposed is based on the edge-illumination concept where a beam of radiation is strongly modulated in amplitude immediately before it reaches the sample. The beam(s) created in this way are then aligned in such a way that approximately 50% of the intensity is lost on an absorbing edge(s) that is placed immediately before the detector pixels. Phase modulations imparted by the sample to the beam are translated into intensity modulations by the apparatus and can therefore be detected, analysed and interpreted.The possibilities opened, should the proposed methodology be successful, are vast, extending the huge potential of neutron radiography to those samples where absorption does not offer a sufficiently large signal.
DOI: 10.5286/isis.e.rb1720167
title: Residual Stress Measurements in Inc718 and C263 Nickel Based Super-Alloys and Jethete Stainless Steel Subjected To Consecutive Spin Forming

description: This project is being conducted at the Advanced Forming Research Centre (AFRC), funded by UK government through the Innovative UK (I-UK) initiative known as Manufacturing Portfolio. The project is investigating the suitability of flow forming technique to manufacture near net shape tubular components with significantly reduced materials wastage, production time and energy consumption. Flow forming can be applied to multiple components used across a variety of industries including aerospace, automotive, oil & gas, and renewable energy. This process is very flexible and can be utilised to produce cylinders, shafts, and gear components.The levels and distribution of residual stresses imparted into samples can give an insight into such process failures and how such failures can be avoided and important aspect of designing components manufacture.
DOI: 10.5286/isis.e.rb1810006
title: Understanding magnetodielectric behaviour of Tb2BaNiO5 using Neutron Diffraction Studies

description: The coupling between magnetic and electric degrees of freedom, in a single phase compound has been of intense research in recent literature, as the outcome would yield novel materials for various applications. Recently, the compound Tb2BaNiO5, has been shown to exhibit exceptional magnetodielectric coupling within this family . This compound undergoes antiferromagnetic ordering at (TN=T1=) 63K . In this recent study , another magnetic transition was observed below (T2) = 25K. Around 15K, that is at T &lt; T2, Tb2BaNiO5 exhibits 18% change in the magnetodielectric effect, which is the largest intrinsic magnetodielectric effect within the R2BaNiO5 family. This was interpreted in terms of an unusual role played by the single-ion anisotropy of Tb ion. A detailed neutron diffraction experiments across the magnetic phase transition temperature of Tb2BaNiO5 is planned.
DOI: 10.5286/isis.e.rb1810012
title: COMBINED QUASI-ELASTIC NEUTRON SCATTERING AND SR-INFRARED MICROSPECTROSCOPY FOR IMPROVING CHEMOTHERAPEUTIC SUCCESS AGAINST OSTEOSARCOMA

description: This is a joint ISIS/DLS proposal  Quasi-elastic neutron scattering (QENS) and SR-Infrared microspectroscopy (SR-IRMS) are coupled to probe the impact of a Pd(II) anticancer agent on human osteosarcoma, which is the most common primary bone tumour in children and teenagers, with a low success available treatment. This study aims at attaining a thorough understanding of the cytotoxic profile of unconventional cisplatin-like drugs, at a molecular level, from the effect on cellular metabolism to the influence on intracellular water (that can affect vital biochemical processes within the cell and therefore be regarded as a secondary drug target). This is an innovative way of tackling the drug´s pharmacodynamics, aiming at an improved chemotherapeutic activity. The proposed study builds on several successful experiments previously performed for this type of systems at both ISIS and DLS.
DOI: 10.5286/isis.e.rb1810139
title: Probing the Effect of Applied Field on Magnetocaloric Tb(HCO2)3

description: The 1D ferromagnetic coupling within the chains of Tb(HCO2)3 appears to play a key role in its greater magnetic cooling performance above 4 K, compared to Gd(HCO2)3. Furthermore below 1.6 K the packing of these ferromagnetic chains into a frustrated antiferromagnetic triangular lattice appears to enable the emergence of long range 1D magnetic order with only short range antiferromagnetic correlations between its chains; a state resembling a triangular Ising antiferromagnet. The effect of applied magnetic fields on the combination of low dimensional  and frustrated magnetism in Tb(HCO2)3 is unknown and we aim to probe this in both its ordered and paramagnetic states using the WISH diffractometer, taking advantage of this instruments high resolution and intrinsically low background to accurately measure changes in its magnetic scattering at fields up to 5 T and between 1.5 and 20 K.
DOI: 10.5286/isis.e.rb1810152
title: Local ordering in copper antimony tin sulfide thermoelectrics

description: Solid-state devices based on thermoelectric materials can directly convert heat into electricity and may be utilized to make use of waste heat, for example from industrial processes and vehicles. We have been investigating the thermoelectric properties of compounds based on copper antimony sulfide, Cu3SbS4 (famatinite). The system shows a dramatic increase in thermoelectric properties when Sn is substituted for Sb in the system Cu3Sb1-xSnxS4-y (0.0  x  1.0). We have collected neutron diffraction data on two mixed metal compositions in this system and found not only does the local structure differ significantly from the average crystallographic model, but also changes with composition. A total neutron scattering study of the end member compositions is proposed to resolve details of local structures that can be used to aid in the analysis of the mixed metal systems.
DOI: 10.5286/isis.e.rb1810312
title: µSR investigations of magnetoelectric 4d-based dimer system Ba3NdRu2O9

description: The magnetic ground state of a compound containing higher d-orbital (4d/5d) is fascinating due to its  various competing effects like extended orbital, pronounced crystal field effect and strong spin-orbit coupling, and thereby, exhibits many exotic phenomena. Here,  we we plan to investigate Ruthenium-based dimer system, Ba3NdRu2O9, which exhibits complex magnetism, such as, possibility of spin-gap even below long-range ordering, short-range magnetic correlation above ordering and strong magnetoelectric coupling (the cross-coupling between magnetism and dielectric). The proposed muSR investigation down to 2 K in zero-field and longitudinal field of 40 KOe will enable us to understand the nature of magnetic ground state, the exact spin dynamics below and above magnetic ordering temperature; further, this will shade light on the mechanism of magnetoelectric coupling  in this system.
DOI: 10.5286/isis.e.rb1810365
title: Dynamics of Solid Ionic Conductors: Na2Si2O5 and Li2Si2O5

description: We would measure vibrational spectra for Li2Si2O5 and Na2Si2O5, as well as quasielastic neutron scattering (QENS) spectra for Na2SiO5. The measurement of phonon spectra in the entire Brillouin zone over the temperature range of 300-1300 K is required for characterizing the specific phonon modes relevant to the ionic conductivity and thermal expansion behavior. The measurements would help to identify the phonons which show significant changes as a function of temperature. In addition, we propose to understand the diffusion pathways and timescales by QENS. By combining the vibrational and QENS measurements (300-1300 K) with first-principles phonon calculations and temperature-dependent molecular dynamics simulations, we expect to gain deeper insights of the origin and mechanism of ionic conductivity in amorphous phase and their relationship to phonons in these compounds.
DOI: 10.5286/isis.e.rb1810446
title: Orbital selective neutron spin resonance in underdoped Ba(Fe0.952Co0.048)2As2

description: The microscopic origin of neutron spin resonance remains one of the major debates in iron-based superconductors. The spin resonance in iron pnictides is generally interpreted as a spin exciton arising from sign-reversed quasiparticle excitations between hole (at Г point) and electron (at X and Y points) Fermi surfaces. Our recent study on detwinned electron-doped NaFe0.985Co0.015As has revealed that he spin resonance in this system is dominated by the interband scattering with only dyz orbitals. Because of the differences between various iron-pnictide systems (such as structure and Fermi surfaces), the symmetry and orbital character of the spin resonance modes in other systems are still unclear and remain to be explored experimentally. Therefore, we propose to explore the orbital character of the spin resonance mode in electron-underdoped Ba(Fe1-xCox)2As2.
DOI: 10.5286/isis.e.rb1810588
title: Structure of biocompatible fluorescent microemulsions

description: Building from work previously carried out at ISIS (RB1410544) and pulished open-access in Chem. Commun. 2016, 25, 7344, we propose a SANS experiment to investigate the structure of droplets of a highly fluorescent liquid pyrene dispersed in water using various biocompatible surfactants. These systems have shown promise as replacements for nanoparticle or solubilised dye dispersions in biomedical fluorescent imaging (in-vitro or in-vivo). Knowing how parameters such as temperature and composition alter the droplet size and shape will allow us to tune the fluorescent properties and may allow targeting of specific biological regions for imaging.
DOI: 10.5286/isis.e.rb1810623
title: Single Crystal Scattering Study of 163-Dy2Ti2O7 Using SXD

description: Spin ice materials are a class of compounds with exotic magnetic properties, resulting from the frustration. Magnetic monopoles have been detected at low temperature; manifest as quasi-particle excitations. A specific heat study of the natural abundance of Dy2Ti2O7 found an upturn at long timescales (&gt;10000 s) below 0.6 K, suggesting the emergence of previously unobserved ordering, and the break-down of the spin ice phase. We have studied the specific heat of 162,163 and the natural abundance and find no evidence for this phase transition. However, when we implement corrections for the hyperfine interaction, we find some difference between 162 and 163. One explanation for the difference in specific heat is a difference in the oxygen defect structures. Having already studied 162 on SXD, we propose a diffuse scattering study of 163 to explain our data.
DOI: 10.5286/isis.e.rb1810641
title: Crystal field excitations on Sm based pyrochlores

description: The A2B2O7 pyrochlore family, where A is a rare earth ion and B=Ti, Sn, is one of the most prolific series of compounds presenting magnetic frustration. The geometric Fd-3m cubic lattice constrains the magnetic moments to arrange in configurations to which the minimum free energy of all the competing interactions cannot be minimised. The Sm based pyrochlores are relatively unknown due to the high neutron absorption cross-section of the samarium ions, what complicates the magnetic characterisation of the material. We have sinthesized isotope enriched samples and some curious previous results show that Sm based pyrochlores are worth being studied.
DOI: 10.5286/isis.e.rb1810758
title: Gamma Dopplerimetry to Determine the Environment of Iodine in Halogen Bonded Monolayers on Graphite

description: Molecular self-assembly directed by non-covalent interactions presents a unique opportunity to create precisely engineered functional materials. Halogen bonding is a widely studied interaction in three dimensions but there is limited research in two dimensions. It can be comparable in strength to the hydrogen bond but with the potential to be more selective it appears to be an excellent candidate interaction for designing functional materials. Previous work by the Clarke group has focused on the structure of physisorbed layers on graphite but there is little experimental work on the strength of bonding within these layers. This proposed experiment, seeks to use gamma dopplerimetry to determine the atom projected vibrational density of states for iodine in three halogen bonded monolayers on graphite and, via computer models, gain a measure of the strength of halogen bonding.
DOI: 10.5286/isis.e.rb1810807
title: Muon spin rotation/relaxation study of  newly discovered  novel layered superconductor NaSn2As2

description: The low dimensionality affects the electronic structure of materials, which could realize a high transition temperature or unconventional pairing mechanisms. Recently Mizuguchi et al. discovered the superconductivity in a layered tin arsenide NaSn2As2. Measurements of electrical resistivity and specific heat confirm the bulk nature of superconductivity of NaSn2As2 with Tc=1.3 K. In this compound the SnAs layers will be a basic structure providing another universality class of a layered superconducting family, and it provides a new platform for the physics and chemistry of low-dimensional superconductors with lone pair electrons. We propose to use zero-field, transverse field and longitudinal field muSR to investigate the microscopic superconducting properties, such as symmetry of electron pairing, carrier effective mass and time-reversal symmetry of NaSn2As2.
DOI: 10.5286/isis.e.rb1820116
title: INS study of the first carbon-carbon bond formation stage in the methanol-to-hydrocarbons reaction.

description: Methanol-to-Hydrocarbons is an industrially relevant reaction. The generally accepted mechanism under steady state is the 'hydrocarbon pool' mechanism with the hydrocarbons acting both as the activating and deactivating species. How the first carbon-carbon bond is created is still under heavy debate. Recent literature has focused on the theory of the first C-C bond being created via a direct mechanism with methyl acetate and surface adsorbed acetate species as the intermediate. In this INS study we propose to use the ISIS/Glasgow catalysis rig in order to prepare MTH reacted samples where methanol is co-fed with methyl acetate in order to study how the increased presence of methyl acetate in the feed will change their vibrational spectra. The samples will also be analysed via TPO, NMR, FTIR and EPR provided through the projects collaboration with the UK Catalysis Hub and Johnson Matthey.