cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1520431
title: Muon spin rotation and relaxation studies of the filled skutterudite superconductor LaOs4As12 and LaRu4As12

description: The understanding of the pairing mechanism in unconventional superconductors is a major theoretical challenge. Recent muon-spin relaxation measurements of the heavy-fermion superconductor filled-skutterudite PrOs4Sb12 reveal the spontaneous appearance of static internal magnetic fields below the Tc, providing unambiguous evidence for the breaking of time-reversal symmetry in the superconducting state. LaRu4As12 and LaOs4As12 is also a filled-skutterudite compound, with Tc = 10.3 K and 3.2 K respectively.  The Tc of LaRu4As12 (multiple superconducting gaps) is the highest in these compounds. For LaOs4As12 the temperature dependences of the nuclear spin?lattice relaxation rates of 75As nuclei can be understood in terms of antiferromagnetic spin fluctuations (ASF). We want to study these compounds by zero-field and transverse field µSR technique using MUSR spectrometer.
DOI: 10.5286/isis.e.rb1610048
title: Microstructure of self-assembled polymer nanoparticles in non-polar solvents

description: Polymerization-induced self-assembly (PISA) is a versatile method that enables the synthesis of diblock copolymer nanoparticles in many solvents. In particular, sterically-stabilized spherical nanoparticles in non-polar solvents represent an interesting model system. We recently prepared a series of such spheres with mean diameters that strongly depended on the degree of polymerization of the stabilizer block. Recently, spin-echo small-angle neutron scattering (SESANS) has been shown to enable precise characterization of the microstructure of polymer colloids. We plan to use this technique to study the structure of poly(stearyl methacrylate)-poly(benzyl methacrylate) (PSMA-PBzMA) spherical nanoparticles to assess the morphology of the stabilizer and core-forming blocks and the degree of solvation, connecting the localized polymer structure to the final nanoparticle size.
DOI: 10.5286/isis.e.rb1610175
title: Clarifying the magnetism of two polymorphs of Ca2Os2O7 by muon spin rotation

description: This proposal is part of our project to investigate the unusual physics of 5d transition metal oxides. In particular, we are studying two samples of the chemical composition Ca2Os2O7: One forming the pyrochlore and the other the weberite crystal structure. The key interest in these materials are unusual metal-insulator (possibly Slater or Lifshitz) transitions, concomitant with magnetic ordering. For both samples, we have already performed extensive bulk characterisation and neutron diffraction experiments (and, for the pyrochlore, a preliminary MuSR measurement). However, in both cases, the experimental evidence is ambiguous and we believe that muon spin rotation will yield the desired answers: (1) For the weberite, we want to determine whether the two osmium sites order simultaneously and (2) For the pyrochlore, we want to determine whether any long range order sets in above 40 m
DOI: 10.5286/isis.e.rb1610182
title: Spin-Driven Multiferroics CdMn7O12 and SrMn7O12

description: We propose to perform neutron diffraction experiments on powder samples of possible spin-induced multiferroic materials, 114CdMn7O12 and SrMn7O12, at ambient pressure and low temperatures. A giant improper ferroelectricity was discovered in 2012 in CaMn7O12 with the polarization value of P = 2870 microC/m2. This discovery has stimulated a lot of interest toward CaMn7O12. We have recently described the high-pressure high-temperature synthesis, crystal structures and properties of CaMn7O12 analogues, CdMn7O12 and SrMn7O12. And we have found differences in magnetic properties, dielectric properties, ferroelectric properties and hysteresis behavior among CdMn7O12, CaMn7O12 and SrMn7O12. To understand the differences among AMn7O12 perovskites with A = Cd, Ca, Sr, and Pb, information about magnetic structures of all members is needed.
DOI: 10.5286/isis.e.rb1610281
title: Searching for magnetic order in two nitronyl nitroxide isomers

description: Using nitronyl nitroxide radicals it is possible to prepare purely organic ferromagnets without inclusion of any transition metal or lanthanide ions. Muons are uniquely sensitive to the magnetic properties of these materials; they are highly suitable for study at ISIS because the internal fields are typically low. Two isomers have been identified as showing dramatically different magnetic properties (one is two-dimensional, the other consists of an array of dimers) which we believe occurs because of the different packing of the radicals. The aim of the experiment is (i) to determine whether the 2D arrangement of radicals shows magnetic order and (ii) to investigate the intriguing possibility that for the other system, the muon could attach via a muonium state, thereby splitting the dimer. These possibilities will be investigated experimentally, comparing results with DFT+mu calculations.
DOI: 10.5286/isis.e.rb1610352
title: Searching for time-reversal symmetry breaking pairing state in non-centrosymmetric ternary half-Heusler compound LuPdBi

description: LuPdBi, a ternary half-Heusler compound, is superconducting at 1.7 K and has an upper critical field of 2.2 T. Specific heat data suggests that superconductivity of LuPdBi is fully gapped with possibly unconventional pairing character. Crystal structure of LuPdBi is non-centrosymmetric. The presence of Pd and Bi in this compound favors strong spin orbit coupling due to the heavy mass of the atomic constituents. The missing inversion symmetry along with strong spin orbit coupling make this material an ideal candidate to study for TRS breaking superconductivity. Here we propose to investigate the magnetic and superconducting properties of LuPdBi using mSR technique. We propose to search for time-reversal symmetry breaking fields by ZF-µSR and pairing symmetry by TF-µSR measurements of LuPdBi. We ask for 5 days of MuSR beamtime for this project.
DOI: 10.5286/isis.e.rb1620008
title: Molecular Dynamics in Polystyrene

description: The goal of this experiment is to better understand the molecular dynamics in polystyrene in order to shed light on the discrepancy between beta-NMR and low-energy muSR experiments on the depth dependence of enhanced dynamics near a free surface. We propose to measure the temperature dependence of the muon relaxation in a weak transverse field (1/T2), which we believe will be more sensitive to probing the molecular dynamics than measurement of the muon relaxation in longitudinal field. The temperature dependence of 1/T2 will allow us to determine the parameters for torsional motion of the phenyl rings and will be compared with the results of beta-NMR and neutron scattering experiments. The results of the proposed experiment will allow us to submit a proposal to PSI to remeasure the depth dependence of enhanced dynamics in polystyrene on LEM and resolve the controversy.
DOI: 10.5286/isis.e.rb1620074
title: Spin ordering in strongly geometrically frustrated magnets YCa3(MO)3(BO3)4 (M = Ti3+, Fe3+)

description: Geometrically frustrated magnetism (GFM) occurs in systems where magnetic cations (spins) are located on a lattice with a triangular geometry and there are antiferromagnetic interactions among them, such that the three neighbouring spins on the triangle cannot be simultaneously antiparallel to each other. The large ground state degeneracy of such systems makes them an interesting platform explore the possible ground states and their entanglements.  This proposal seeks to establish if spin ordering occurs in the frustrated systems YCa3(MO)3(BO3)4 (M = Ti3+ and Fe3+) that contain a 2D kagomé type lattice at very low temperatures.
DOI: 10.5286/isis.e.rb1410458
title: Temperature dependence of magnetic dead-layers: a possible route to novel 2D magnetism

description: We propose to investigate the temperature dependence of magnetic dead-layer thickness in amorphous ferromagnetic CoFeTaB films on Si and GaAs semiconductor substrates. Magnetic dead-layers, particularly in ferromagnetic films on GaAs, are important for hybrid spintronics applications. However, no previous investigations have studied the temperature dependence of the dead-layer thickness. In our low-Curie-temperature films, the magnetic dead-layer may also be important in understanding more exotic magnetic behaviour. Thin films exhibit behaviour characteristic of 2D magnetism, and the magnetic anisotropy induced by the interface with GaAs potentially produces novel anisotropic 2D behaviour. Following our preliminary measurements on thicker CoFeTaB films, we plan to study thinner, quasi-2D, films in order to understand the unconventional and exotic magnetic behaviour in these materials.
DOI: 10.5286/isis.e.rb1520039
title: Paving the way for Methane Hydrate formation in the confined nanospace of metal-organic frameworks

description: The main goal of the present proposal is to evaluate the methane hydrate formation in nanocavities of ZIF-90 using inelastic neutron scattering (INS) measurements. Recently, we have measured in TOSCA the formation of methane hydrate on ZIF-8. We have found that the methane hydrate is formed at the external surface. The exclusion of the hydrate formation process from the inner cavities of ZIF-8 is due to the highly hydrophobic nature of ZIF-8 that avoids the water to access the porosity. Potentially, the methane storage capacity would be further improved if the internal volume of the ZIF is also used for hydrate formation. It is well known from literature that ZIF-90 can be filled with water at high relative pressure (&gt;0.4), indicating weak MOF-water interactions. From our previous knowledge, this MOF might be postulated as a promising material to growth methane hydrate inside.
DOI: 10.5286/isis.e.rb1520071
title: Adsorption of benzotriazole onto copper/copper oxide surface from non-aqueous media

description: Benzotriazole (BTAH) has been known to be a very effective corrosion inhibitor for copper and its alloys. Adsorption of BTAH from oil is a relatively less researched area despite of its many applications in non-aqueous media as a corrosion inhibitor. The poor solubility of BTAH in non-polar organic solvents often necessitates usage of a solvent mixture, comprising of a polar and a non polar component, thus complicating the adsorption behaviour of BTAH. This proposal aims to probe the adsorption of BTAH at the copper/copper oxide surface to acquire compositional and structural information of these important adsorbate layers in oil.
DOI: 10.5286/isis.e.rb1520155
title: Liquid Nanostructure and Amphiphile Self-Assembly in pre-Ouzo Ternary Mixtures

description: Ionic liquids (ILs) - salts that melt  near room temperature - have remarkable properties as solvents for a wide variety of molecules and ions. ILs share with water the rare ability to promote formation of surfactant micelles and lipid bilayer membranes, but some also display amphiphilic (surfactant-like) character. We will examine the structure of mixtures of ionic liquids with water and with model amphiphilic compounds such as ethanol and octanol. This will enable us to understand the intermolecular forces that drive self-assembly by ionic liquids and by other molecules in ionic liquids, and also how this compares with self-assembly in water. These mixtures have widespread applications, ranging from drug delivery systems to foods to polymer composites and filtration membranes. Understanding their molecular arrangements, will enable improvements in the next generation of applications.
DOI: 10.5286/isis.e.rb1520207
title: Study of the interfacial self-assembly of peptide/polymer membranes by neutron reflectivity methods

description: The interfacial self-assembly between large (polymer) and small (peptide) molecules of opposite charge results in the formation of highly organized membranes. Furhter manipulation of the peptide sequence leads to membranes with distinct surface morphologies, from well-defined micro-grooves to micro-sized aggregates.This proposal aims to investigate how peptide sequence controls the behavior and organization of peptide amphiphiles at the air-water interface and understand their interactions with aqueous polymer solutions.The ability of modulating the surface topography of self-assembled membranes, by introducing subtle changes in the peptide sequence, offers a simple way to develop patterned thin soft membranes with great potential for biomedical applications.
DOI: 10.5286/isis.e.rb1520327
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.rb1520341
title: How does the anti-tumor drug paclitaxel change the dynamics on breast cancer cells?

description: Cells are complex systems where small fragments play an interdependent role. The functionality of these systems can be distinct at different length and timescales, depending on physiological conditions or cells type. For example, cancer cells are more flexible than the healthy ones. Thus, understanding cancer cells flexibility is the first step to elucidate how and why they migrate and adhere to different tissues. Another point about the dynamics of cancer cells is the mechanism of action of the drug paclitaxel that bonds to the structural framework of cancer cells, the cytoskeleton, and inhibits their motions and division. Then, a cancer cell treated with paclitaxel should present changes on flexibility. Understanding such changes at distinct timescales might provide additional information on paclitaxel´s action and support the development of new and less toxic drugs.
DOI: 10.5286/isis.e.rb1520388
title: Fluoride uptake by polyaniline films for water purification and remediation

description: The beneficial effects of fluoride are well known, but higher levels are dangerous to health. Existing remediation methods used to address the latter situation all have limitations. This experiment explores the underlying fundamentals of an alternative defluoridation technology based on redox-driven ion exchange, here into polyaniline films. The proposed measurements include static observations of fluoride distribution at different stages of uptake from NaF and ejection into HClO4; based on nanogravimetric data, solvation state changes are also predicted. The experiment then extends to dynamic observations of uptake and ejection using event mode acquisition during slow scan voltammetric scans. Contrast between polymer and solvent will be achieved using d5-aniline. The outcomes are relevant to design of materials and devices for production of drinking water in remote locations.
DOI: 10.5286/isis.e.rb1520394
title: The use of magnetic contrast layers for neutron reflectivity to investigate non-lamellar lipid liquid crystalline nanoparticle interactions

description: The search for new clever ways to deliver drugs, which often are not possible to dissolved in water, has lead to the development lipid based small particles. These particles can dissolve many different types of drugs that so far has been hard to solubilize. They can be used on the skin, eaten and be injected. Although they are based on natural lipids they have an intriguing internal structure which explains the capability to solubilize the drugs. They are also sticky and can be design so that the interacts with cells, more specifically with the cell-membrane that keeps the cell intact. The cell membrane also consists of lipids, so we want to know how the particles interact with these membrane. We are here using models of membranes with different properties and we use neutrons to see what happens when the drug delivery particle meets the membranes.
DOI: 10.5286/isis.e.rb1520410
title: Heterogenous reactions between gas-phase hydroxyl radicals and organic films at the air-water interafce of an atmospheric droplet

description: Projected climate change is strongly influenced by clouds. The oxidative processing of pollutants in clouds affects droplet size and reflectivity, important climatic effects. Clouds contain naturally occurring lipids forming films on the droplet. Oxidation and removal of this film can prevent precipitation and cause cloud evaporation. Oxidation by gas-phase hydroxyl radical will be contrasted with aqueous phase hydroxyl radical. We will study the kinetics of hydroxyl radicals with a proxy film DSPC at the air-water interface. Specifically, (a) is aqueous oxidation from below the film faster or slower than gas-phase oxidation from above, (b) estimate the atmospheric lifetime of thin film at the air-water interface of aerosol with respect to gas-phase hydroxyl radical oxidation. Provide initial kinetics estimate for further experiment of optically levitated aerosol at LSF-RAL.
DOI: 10.5286/isis.e.rb1561023
title: The Victoriatus: a Roman coin made for the Greeks and the Celts
DOI: 10.5286/isis.e.rb1610031
title: The origins of Biosurfactant self assembly

description: Biosurfactants are becoming more commonplace in pharmaceuticals, vaccines and other forms of medicines. With the biobased economy growing substantially and pressure to reduce reliance on palm and crude oil derived materials, it is vital that the Home and Personal Care industry develops frameworks for deploying sustainably sourced alternative materials. Biosurfactants tend to be very similar to nonionic and mild anionic surfactants but with significantly higher molecular weights, generally more than double that of the most commonly used conventional surfactants. We have observed that like their synthetic counterparts these molecules self assemble into liquid crystalline like structures and the aim of this work is to progress towards understanding the way that the molecular architecture drives this mesostructure formation.
DOI: 10.5286/isis.e.rb1610099
title: SANS study of lipid-based nanocarriers as inhaled drug delivery systems for anti-tuberculosis chemotherapy

description: The present project aims to achieve a more detailed structural characterization by SANS of Solid Lipid Nanoparticles (SLN) and liposomes in a perspective of an inhaled anti TB-therapy by means of DPI (dry powder inhaler) or MDI (metered dose inhaler) devices. This study will allow a deeper stuctural understanding of the placement/aggregation of rifampicin and isoniazid drugs into lipid vesicle carriers in order to reach a better knowledge of the encapsulation efficacy, stability into nanoparticles that strongly affects their antitubercular potentiality. These outcomes will be useful also for conceiving further co-loading experiments of two drugs in the same nanoparticle, which would allow a synergistic action after their local lung administration. Moreover, this analysis will provide us key information on the morphology of the lipid shell correlated to the loaded drug placement.
DOI: 10.5286/isis.e.rb1610164
title: Magnetic correlations and possible quantum ground state in a pyrochlore osmate

description: Magnetic order is a property of crystalline materials which contain systems of coupled magnetic moments. In materials known as geometrically frustrated magnets there exist coupled magnetic moments but they do not order because there is no one ordering pattern which is more favourable than others. Materials having the cubic pyrochlore structure often behave like this. We have studied a cubic pyrochlore containing osmium and found evidence for magnetic correlations but no magnetic order down to 1.6 K. Osmium in this material is special because the moment tends to fluctuate due to quantum mechanical entanglement of spin and orbital angular momentum. We will use muon spin relaxation to determine whether our osmium pyrochlre orders magnetically below 1.6 K, and to try to understand whether magnetic frustration and quantum fluctuations are responsible for the suppression of magnetic order.
DOI: 10.5286/isis.e.rb1610203
title: Understanding Li-Diffusion and Resultant Magnetism Within Li Intercalated into Hexagonal Boron-Nitride.

description: This study involves attempting to understand the Li atom diffusion within Li-intercalated hexagonal boron nitride. Muons present a significant advantage as they are sensitive to the Li nuclear moment and any diffusion can be tracked; using neutron scattering is not possible due to the high amounts of boron within the sample! At low temperatures there appears to be features within the magnetisation measurements to suggest that some magnetic ordering is present. This proposal will address whether the freezing of the Li atoms within the lattice leads to the onset of a magnetic state. Muon spectroscopy will also hopefully allow characterisation of this magnetically ordered state and whether the suggested glassiness implied by the varying quenching rates within the magnetisation measurements is in fact true.
DOI: 10.5286/isis.e.rb1610274
title: pH-driven self-assembly of colloidal particles confined between parallel walls

description: Small particles with dimensions of a few hundred nanometers tend to behave differently when confined in small spaces. Examples of such situations are easy to find in nature -- red blood cells flowing in capillaries come to mind -- and in modern technologies. When confined, small objects may spontaneously form ordered structures or they may find it impossible to move in the way they do in a larger space. We have found evidence that the electric charge on such small particles can strongly influence how they arrange themselves between two parallel walls and we want to use neutrons to understand this phenomenon. A better understanding of a system like this may lead to improvements in technologies ranging from lubrication to the healing of fractures.
DOI: 10.5286/isis.e.rb1610398
title: Cascading magnetization plateaus in monoclinic CoV2O6

description: The aim of this proposal is to understand the origin of the cascade of magnetisation plateaus in monoclinic CoV2O6.  While 1/3 plateaus have been reported in the literature, through a collaboration with Cardiff University we have recently been successful in observing multiple plateaus at lower temperatures.  We aim to map out the magnetic structure of these using the WISH diffractometer at low temperatures.
DOI: 10.5286/isis.e.rb1620185
title: In Situ Structural Study of Low Temperature Synthesised TiP2O7

description: The AX2O7 series has received much recent attention due to its ability to host a wide range of 4+ cations. The members of this series have been shown to exhibit complex structures (including super-structures), and some members show negative thermal expansion at elevated temperatures, including ZrV2-xPxO7. TiP2O7 itself adopts a 3x3x3 cubic superstructure at room temperature, and displays positive thermal expansion upon heating. When synthesised at a low temperature, and also with the addition of V metal, there is no evidence of superstructure in either pattern. Both exhibit an irreversible phase transition upon heating to the apparent ideal cubic structure. This proposal is aimed to investigate the structures of low temperature synthesised TiP2O7 and investigate the unusual structural transition from pseudo-cubic to apparent cubic upon heating.