cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1910447
title: Quantum Spin Liquid in triangular Seff=1/2 rare-earth based antiferromagnets

description: The rise of quantum materials observed in the past decades has been a source of great excitement for condensed matter scientists, with the flourishing of new concepts and electronic phases of matter. In particular the Quantum Spin Liquid (QSL) state has attracted a lot of attention as it shows intriguing collective phenomena such as fractionalized excitations or emergent gauge fields. A new Seff=1/2 rare-earth based material, YbMgGaO4, was recently shown to avoid any spin freezing down to T = 50mK and to display a continuum of excitations. However, the presence of intersite mixing between Mg2+ and Ga3+ has dramatic effects on these low energy excitations.  Here, we propose to use µSR spectroscopy to confirm two new Seff=1/2 triangular compounds (KYbVO and KCsYbPO) that are free of such defects as quantum spin liquid candidates and further probe their spin dynamics at low temperatures.
DOI: 10.5286/isis.e.rb1610107
title: Structural study of liquid Ge-Sb-Te alloys

description: Ge-Sb-Te chalcogenide alloys are important for applications in advanced (non-volatile) random-access memory based on a reversible switching between the crystalline and amorphous phases. As the amorphisation occurs via the liquid state, a detailed knowledge of the liquid structure is essential for understanding the glass formation. We aim to investigate the atomic structure and temperature-dependent structural changes in liquid alloys from GeTe-Sb2Te3 pseudo-binary system. The principal questions concern the local atomic ordering in the liquid phase and atomic dynamics. The atomic structure will be investigated by combining different experimental data (NDIS, XRD, EXAFS) in the framework of reverse Monte-Carlo simulation technique. Atomic dynamics will be studied by dynamic viscosity measurements and ab initio molecular dynamics calculations supported by structural data obtained.
DOI: 10.5286/isis.e.rb1610112
title: Hydrogen and deuterium (un)loading kinetics in nano-layered hafnium for hydrogen sensing applications

description: Accurate, safe and cheap hydrogen detectors that can function under a wide range of conditions are required to detect hydrogen concentrations well below this explosive limit are a vital ingredient for the future hydrogen economy. A Novel way to detect hydrogen that is cheap and safe is using optical detectors based on thin film hydrides. Recently, we considered the use of hafnium as a potential sensing material. We find that it is capable of detecting hydrogen under an extremely wide sensing range. However, the relation between optical transmission and the applied hydrogen pressure is not well understood. Additionally, we find large differences between the use of hydrogen and deuterium as a loading gas. To acquire more knowledge, we propose to study a hafnium nanolayer with neutron reflectometry to get more insights in layer thicknesses and hydrogen content of the hafnium layer.
DOI: 10.5286/isis.e.rb1610146
title: PNR study on the exchange bias propagation in the FM/AFM/FM trilayer with a thick AFM

description: Today, a number of technological devices, such as the readout sensor in the hard disc drive, have used the exchange bias (EB) effect, which arises in a ferromagnetic/antiferromagnetic (FM/AFM) bilayer. From both the fundamental and application interests, the study of EB effect in the FM/AFM/FM trilayer can be used to reveal the moments structure of AFM layers and origin of the EB effect itself. Although it is found that the interlayer coupling seems arise across the AFM layers in such trilayer on the basis of the EB studies in the past decade, some issues such as the exist of EB propagation is still not fully understood, partially due to the lack of the knowledge of magnetic structure and the related interlayer coupling across the AFM layer. In this proposal, we wish to understand the magnetic structure of the biased trilayer as a function of the AFM thickness.
DOI: 10.5286/isis.e.rb1610181
title: Emerging quantum spin liquid state in a molecular rotor system

description: Large quantum fluctuations might drive magnetic systems to disordered phases even at low temperatures. Recently, a few two-dimensional spin-1/2 systems have been realized in which the isotropic triangular lattice results in the emergence of the quantum spin liquid state.We investigate the spin state of a layered organic material, (EDT-TTF-CONH2)2+[BABCO]- by multi-frequency electron spin resonance measurements. The (EDT-TTF-CONH2)2+ sites form a closely isotropic triangular lattice, and the Brownian motion of the molecular rotor BABCO- layers provoke large dipole fluctuations. We found no indication of magnetic ordering or spin freezing down to 1.5 K. Our results suggest that, due to the intrinsic disorder, a unique QSL state is formed. To verify the absence of the ordering, we intend toperform high-precision muon spin rotation experiments down to 30 mK in low magnetic fields.
DOI: 10.5286/isis.e.rb1610318
title: What really governs porosity in Amorphous Solid Water (ASW)?

description: This experiment will establish the structural changes that occur in Amorphous Solid Water (ASW), a porous material that can be formed by vapour-depositing water onto a cold plate. We will study the temperature and temporal evolution of this metastable condensed-matter material, particularly in an astrophysical context, looking at how the pores within the ice change size, shape and spacing, depending on the temperature. The experiment exploits the unique Q-range capabilities of NIMROD, capable of determining both the micro- and meso-scale structure of samples concurrently.  The results will be of importance in understanding the properties of ASW, the most commonly encountered form of water in the universe, and how the ice structure at low temperatures impacts on the chemistry and physics that can be occurring during planet and star formation.
DOI: 10.5286/isis.e.rb1610442
title: A study on atomic clustering in Fe-Cr alloys by NIMROD diffractometer

description: Low temperature embrittlement of stainless steels are due to phase separation and it is known that the kinetics of phase separation depend on the initial structure. However, the effect of initial clustering occuring above the miscibility gap on subsequent phase separation kinetics is not known. Hence, this will be further investigated in the present proposal. A better knowledge of this phenomenon will assist in further developing predictive modeling that can be used for novel alloy design.
DOI: 10.5286/isis.e.rb1720145
title: Investigating the dynamics of substituted aromatic liquids confined in Pt/MCM-41

description: This proposal would investigate the dynamics of ortho-/meta-/para- xylene, mesitylene and 1,3,5-trihydroxybenzene confined in the catalyst Pt/MCM-41. The relatively wide pores of MCM-41 (30 - 50 Å) compared with other industrially relevant supports such as ZSM-5 (5 Å) allow these bulky guest molecules to diffuse more freely. This has particular implications for catalysis as the diffusion of the molecules to and from the active site is often the slowest step. Further information of the dynamics of these confined species could provide insight into the design of more efficient catalysts. The confining of these fluids inside the pores of MCM-41 will alter its physiochemical properties influencing the transport properties of the guest molecules.
DOI: 10.5286/isis.e.rb1720168
title: Structural characterisation of a pyrochlore solid solution in the Na2O●Bi2O3●TiO2 system

description: 3 days on POLARIS are requested to study three pyrochlore compositions in the Na2O●Bi2O3●TiO2 system that has been reported only once in the literature, without any characterisation. Unpublished electrical data shows low conductivity comparable to insulating Na0.5Bi0.51TiO3+δ perovskite but much lower than oxide-ion conducting Na0.50Bi0.49TiO3-δ (NB49T) even though the oxygen vacancies concentration in the pyrochlores is much higher. In dielectric measurements, relaxor behaviour is observed near room temperature. Variable temperature Neutron diffraction should enable to determine the unit cells, ion displacements and occupancies. This information will be valuable to comprehend the dielectric behaviour and electrical conduction mechanism(s) in this and other NBT related systems.
DOI: 10.5286/isis.e.rb1720206
title: Formation of cellulose-starch gels: effect of cellulose source and surfactants

description: This proposal forms part of an ongoing project concerning interpenetrating network gels of starch and cellulose being developed towards applications in personal care and agrochemicals based on the interests of our industrial partners. Addition of soluble starch polymers to partially oxidised cellulose (oxcel) suspensions creates gels with increased viscosities over single component suspensions. We aim to build on our previous studies of oxcel gels by determining changes in gel network structure and properties when soluble starch, anionic surfactant and salts (which are known to gel the oxcel fibrils), are added. Selective deuteration will enable us to highlight oxcel gel structures, the starch network and the location of starch and anionic surfactant within the oxcel network. Structural results will be combined with rheological measurements to improve formulation using these materials.
DOI: 10.5286/isis.e.rb1720338
title: Lipid dynamics in raft domains and effect of an oxidized bilayer component on their formation

description: Lipid oxidation is linked to many adverse health effects. In this proposal we will use QENS in combination with contrast variation as a non-invasive method to detect and characterize the presence and size of microdomains formed in vesicles of biologically relevant lipids as a function of oxidized lipid levels and temperature. The domain forming lipid mixture system to be used in the present study will be composed of a saturated phospholipid, DPPC, an unsaturated phospholipid, POPC, and cholesterol (Chol) where a portion of the POPC is systematically replaced with the oxidized version of POPC, POnPC.
DOI: 10.5286/isis.e.rb1720451
title: MuSR search for fluctuating loop currents in cuprates

description: The origin of the pseudogap region below a temperature T* is at the heart of the mysteries of high-Tc cuprate superconductors.The proposed broken time-reversal and inversion symmetry due to ordered loop currents is consistent with five different classes of symmetry-sensitive experiments. However, MuSR and NMR didn't see the static magnetic fields expected for such an order. By measuring the variation of muon spin relaxation rate in a field oriented along the initial muon spin polarization of single crystals of YBa2Cu3Oy, we have discovered that the field is there, it is just fluctuating. Now we propose to do more MuSR experiments to enrich the phase diagram and investigate the new physics in this system.
DOI: 10.5286/isis.e.rb1720506
title: Modelling decarburization in BF-BOF steel making

description: 70% of the worlds steel production is conducted via the blast furnace-basic oxygen furnace (BF-BOF, Fig 1.) route using raw materials to meet the low residual, low inclusion requirements of the packing and automotive industries. CO2 is an unwanted bi-product of the process produced in high volumes given the scale of production. To comply with green legislation, the steel industry aims to reduce emissions by 50% by 2025 through process improvements and CCS. It is the subject of this proposal to determine the stress and dissolved carbon throughout the bulk bath samples by neutron diffraction. Together with on-going characterization of porosity and the previous model, this data will help determine the cooling rate of the sample and the contribution to CO2 production in the bulk bath of a BOF throughout processing.
DOI: 10.5286/isis.e.rb1720507
title: Chemical effect on elastic properties in hexa-alogenated-benzenes

description: Benzene is the parent compound of organic solids based on C-H...pi interactions that have been used in organic field effect transistors. Any change in the C-H...pi interactions due to chemical environment or isotopic substitution can affect the electronic properties of these materials. Here we propose to study the effect of chemical substitution on the elastic properties of hexa-alogenated benzenes, by analysing  the temperature-dependence of Atomic Displacement Parameters (ADP's) that allows the retrieval of lattice normal mode frequencies from diffraction data.
DOI: 10.5286/isis.e.rb1770001
title: mSR study of impurity effects on the Cu-spin correlation and superconductivity in the undoped superconductor T'-La1.8Eu0.2Cu1-yMyO4(M=Ni,Zn)

description: The purpose of this muSR study is to clarify whether or not the development of Cu-spin correlation by Ni- and Zn-substitution to Cu sites in undoped high-Tc cuprate La1.8Eu0.2CuO4 with the Nd2CuO4-type (so-called T-type) structure.  Recently, we have investigated the impurity effects on superconducting critical temperature, Tc, for polycrystalline bulk samples of undoped T-La1.8Eu0.2Cu1-yMyO4 (M = Ni, Zn).  The obtained results suggest that the symmetry of the superconducting gap is similar to that in optimally doped and overdoped La2-xSrxCuO4 with the K2NiF4-type (so-called T-type) structure.  Therefore, the comparison of results of the SR experiments in both T-La1.8Eu0.2Cu1-yMyO4 and T-La2-xSrxCu1-yMyO4 is expected to give us significant information on the development of Cu-spin correlation in T-La1.8Eu0.2CuO4.
DOI: 10.5286/isis.e.rb1770013
title: Muon characterization of ordered and disordered cathode materials for Li-ion batteries

description: Understanding the transport properties of Li-ion cathode materials is considered crucial in designing high energy density cathode materials for Li-ion batteries. We are particularly interested in designing high capacity Ni-rich and Li-rich transition metal oxide cathode materials. TM ions, especially Ni, tend to diffuse between its own layers and the Li layers (interlayer mixing), creating disorder in the structure. This disorder prevents the free diffusion of Li ions during charge and discharge and is hence detrimental to the performance of cathode materials. There have been no experimental studies to probe the effect of this disorder on the hopping rates of Li and thus the voltage profile. Results from this Muon study will shed light into how disorder affect the Li hopping rates and thus the voltage profile of the Li-ion battery.
DOI: 10.5286/isis.e.rb1810057
title: In search for magnon-magnon/phonon coupling in metallic triangular antiferromagnet CrB2

description: Recent theories and experiments on two-dimensional triangular lattice antiferromagnet show that the spin dynamics of these system exhibit the rare phenomena due to high-order magnon interaction terms. This unuusal interaction can give rise to a so-called Roton-like minimum at the B point in the momentum space, a flat mode and finally a magnon breakdown. All these three key theoretical observations have now been borne out by our experiments, done at ISIS. With this sucess, we now want to study a metallic version of the same system. The question here is how the high-order term survies under the sea of condunction electron, in particular with the long-range RKKY interaction. For this study, we propose to investigate CrB2, a metallic triangular antiferromagnetic with TN=88 K and an incommensurate cycloid magnetic order.
DOI: 10.5286/isis.e.rb1810092
title: Investigating the spin-nematic phase in the 1D quantum spin chain, Linarite

description: Linarite is a natural mineral which displays a rich and complex phase diagram in applied fields up to 10 T for temperatures below 2.8 K. As a frustrated J1-J2 chain material, linarite has been proposed as one of the best candidates for displaying a spinnematic phase due to its accessible saturation field of 9.3 T. Researchers have been searching for such an experimental realization of this dynamic phase, which can be likened to the spontaneous alignment of rod-shaped molecules in Liquid Crystal Display screens. Recent inelastic neutron scattering measurements in zero applied field have shown dispersive properties both parallel and perpendicular to the Cu-chains which have been successfully modeled with linear spin-wave theory. We hope to extend this study to investigate the magnetic field dependence of the excitations close to saturation where we expect to see evidence of spin-nematics.
DOI: 10.5286/isis.e.rb1810166
title: QENS Investigation of Proton Conduction Mechanism in Spark-Plasma-Sintered Protonic Ceramics Based on Doped Barium Zirconate

description: Fuel cells exhibit high-energy efficiency and the only release is clean water when used with hydrogen. Proton ceramic fuel cells (PCFC) are from special interest because proton conductivity occurs already at relatively low temperatures (400°C) with positive effects on the operating time of the fuel cell. Cerium and yttrium doped barium zirconate (BZCY) has emerged as a leading candidate material for fabrication of dense proton conducting ceramics which can be used as electrolyte materials. BCZY exhibits the two required properties for a PCFC electrolyte: a satisfying protonic conductivity and a sufficient stability.We propose to carry out QENS on BZCY fabricated by Spark Plasma Sintering (SPS) to get a better understand of the proton diffusion inside the bulk.  A good insight of the proton hopping mechanisms leads to optimization of the fabrication and eventually the conductivity.
DOI: 10.5286/isis.e.rb1820016
title: Using contrast matching to understand the networks in multicomponent systems

description: We have been focusing on two component gel networks. Here, both components can individually form gels. In a mixed system, the LMWG can either co-assemble or self-sort. In a self-sorted system, the LMWG prefer to assemble with themselves, such that each fibre only contains a single LMWG. However, for self-sorted fibers, to understand the mechanical properties of the gels, it is necessary to understand how the fibres interact. For example, in two hypothetically different cases, the different fibres could heavily entangle or prefer to remain separate and form an interpenetrated network. Here, we intend to use contrast matching experiments to understand how one network has been affected by the presence of the second.
DOI: 10.5286/isis.e.rb1820068
title: Neutron diffraction studies of incommensurate charge ordered phase Pr0.20Sr0.80Mn1-xMoxO3 (x = 0, 0.02, 0.04 and 0.10).

description: The occurrence of multiferroic properties in incommensurately charge and magnetic ordered phases in the narrow band Pr1-xCaxMnO3 has freshly steered the search of newer such phases in manganites. By doping larger size non-magnetic Mo6+ ion at Mn site in a chemically similar manganite Pr0.20Sr0.80Mn1-xMoxO3 (x = 0.0, 0.02, 0.04 & 0.10) we have synthesized electron-doped incommensurate charge-ordered phase for the first time. We want to study the possible magnetic phases in this very system using time of flight neutron diffraction measurements on GEM beamline.
DOI: 10.5286/isis.e.rb1820183
title: Pressure driven phase transitions in antiferroelectric, PbZrO3

description: Antiferroelectric materials are attracting extensive attention due to their potential in energy storage applications. These materials exhibit a double polarisation-field hysteresis loop which allows for high storage capacities with low loss. However, despite this interest we still know very little about the behaviour of antiferroelectrics. Lead zirconate is the prototypical perovskite antiferrolectric. We believe gaining an enhanced understanding of this material will allow us to tune and develop new materials for energy applications. One way to understand the effects of doping (chemical pressure) is to perform high pressure studies. In this way we can probe phase stability and look to replicate exciting phases under ambient conditions. In this proposal we seek to revisit the high pressure phase diagram of lead zirconate.
DOI: 10.5286/isis.e.rb1820191
title: Determination of Detailed Asphaltene Layer Structure to Understand Crude Oil Emulsion Stability

description: Asphaltene, the most polar fraction of petroleum crude oil, is present at concentrations that can vary from virtually zero to 20 % w/w depending on the oil origin. Asphaltene is responsible for numerous problems in the oil industry, such as the formation of water in crude oil emulsions (w/o) during production, transport, and processing of crude oils . In order to improve the methods to break emulsions, it is important to determine how asphaltene stabilizes them. Consequently, the goal of this study is to determine the conformation of asphaltenes at the interface between oil and water using silica surface as surrogate for water.
DOI: 10.5286/isis.e.rb1820538
title: Interaction of the nucleic acid, DNA, with a model biomembranes of varying rigidity at the oil-water interface

description: In this experiment we aim to investigate, using neutron reflectometry in combination with contrast variation, the intermolecular interaction between the nucleic acid, calf thymus DNA monolayer comprised of a mixture of phospholipid(DSPC) with varying amounts of cholesterol at the oil-water interface in the presence of divalent cation. Of particular interest here is the conformational order of the film as function of DNA concentration which will be studied. In particular the effect of membrane rigidity at the oil/water interface has not been resolved to date and is an important aspect of the current project. The information gained in the study will be invaluable in understanding of the structure and transport properties of the cell membrane as well as helping in the development of vehicles to improve the delivery of nucleic acids (i.e. gene).
DOI: 10.5286/isis.e.rb1820581
title: Determination of nuclear quantum effects on the hydrogen adsorption in metal-organic frameworks

description: Metal-organic frameworks represent one of the most studied options to store hydrogen for clean-energy applications. Nuclear quantum effects, and in particular zero-point energies, are responsible for the reduction up to 20% of hydrogen-uptake levels in porous materials with respect to the unrealistic case of classical hydrogen dynamics. Depending on the theoretical approach describing hydrogen adsorption in metal-organic frameworks, such as including or not nuclear quantum effects, the interaction potential between hydrogen and the host can change dramatically, thus affecting the interpretation of results from computer simulations. We propose an experimental determination, using neutron Compton scattering, of the nuclear quantum effects in the hydrogen adsorption in a test metal-organic framework so as to reconstruct the potential-energy surface affecting hydrogen in a model-free manner.
DOI: 10.5286/isis.e.rb1869010
title: Production mechanism of polymersomes

description: In the field of cancer research, radionuclide therapy is proven to be one of the only viable alternatives to chemotherapy in the case of metastasized cancer. In this context, polymersomes are attracting increasing interest as a an alternative to liposomes due to their ability to encapsulate a broad range of drugs, biomolecules and radionuclides. Because of the good synthetic control in the polymer industry, polymersomes, compared to liposomes, have a higher variability as well as an enhanced physical and chemical stability. The main challenge in the production of polymersomes is up scaling the formation process which required understanding of the formation mechanism. We propose to investigate the important steps in the formation mechanism using neutron scattering techniques.