cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1720480
title: Investigating the INVAR behaviour of Pd3Fe

description: INVAR behaviour is the property of having zero thermal expansion over a given temperature range; something very important for certain engineering applications, and very practical in others. The physical process describing this phenomena involves a perfect balance between varying magnetic interactions in the material, and the interatomic separation as a function of temperature. Pd3Fe was recently shown to enter into such an INVAR state when the system is placed under high pressure - we aim to use this to probe the nature of the phase transition to this novel state, to better understand how INVAR materials work.
DOI: 10.5286/isis.e.rb1800008
title: Crystal field excitations of Ce2Ni12As7
DOI: 10.5286/isis.e.rb1800012
title: Hydration and deuteration test of chia seed mucilage aerogel
DOI: 10.5286/isis.e.rb1800022
title: Copy of: The Mechanism of Bam Mediated Outer Membrane Protein Folding

description: The proteins of the outer membrane of Gram-negative bacteria are critical for bacterial survival,from providing basic physiological functions, to impairing virulence and multidrug resistance. The Bam complex has been found to be essential for folding these proteins into the outer membrane.The process by which this is achieved is unknown. The structure of the complex and its individual components are now known. We aim to continue our investigation of the Bam complex by studying BamABCDE in complex with stalled folding intermediates. To do this we will use  specific deuteration and neutron reflectometry in concert with previous polarised neutron reflectometry datasets of the BamABCDE complex bound to a gold surface to probe the structure of the Bam complex as it performs its function.
DOI: 10.5286/isis.e.rb1210218
title: In-situ Neutron Diffraction Studies of Lithium Battery Materials

description: This proposal seeks to test a new battery designed to allow in situ neutron diffraction measurements of lithium ion battery electrodes under charge and discharge. We have developed a new wound cell which contains large amounts of electrode material necessary for high quality diffraction data but arranges them in thin electrodes which will allow fast electrochemistry. All hydrogen containing components have been replaced with hydrogen free alternatives to avoid significant amounts of incoherent scattering.This cell will be used to investigate the structural changes in LiFePO4 at a series of rates. The reduced diffraction pattern collection times afforded by the upgraded Polaris instrument will allow study of high rates of charge and discharge. The cell will then be used to study the slow cycling structural changes occurring in LiFeSiO4 at 55 C during the first charge and discharge.
DOI: 10.5286/isis.e.rb1510101
title: Structure of the fast lithium ion conducting phases of LiInBr4

description: One day of beamtime on GEM will be used to analyse the structure of fast lithium-ion conducting LiInBr4 above and below the phase transition at 53 °C. We will determine the defect structure and Li+/In3+ ion distribution in both phases. The structural changes of the compound from 25-80 °C will be probed for the first time. Moreover, the variable temperature data will provide valuable information on the mechanism of Li+ conduction in the ternary bromide.
DOI: 10.5286/isis.e.rb1510147
title: Investigating semi-metal superconductivity in a Lu3Os4Ge13 single crystal

description: Lu3Os4Ge13 is an interesting superconducting system, with potentially unconventional physics.  It is a low carrier density semi-metal, exhibiting superconductivity at 3.1 K.  This is a continuation proposal, for we have previously conducted a MuSR experiment on a polycrystalline sample of this system.  This led to some exciting results, as time-reversal symmetry appears to have been broken, indicating that this system may exhibit spin-triplet Cooper pairing.  The material also appears to have two superconducting gaps.  This experiment aims to confirm our previous findings on a high quality, single crystal sample, with the potential for an exciting publication and a new direction for superconductor physics.
DOI: 10.5286/isis.e.rb1510200
title: Metal Atom Ordering in Thermoelectric Materials

description: Preparation of materials Co3-xNixSn2S2 (0 &lt; x &lt; 3) has enabled the effect of electron-doping on the thermoelectric properties of shandites to be investigated. DFT calculations suggest that in the mixed-metal phases, a lowering of energy is achieved through ordering of nickel and cobalt atoms. For example at x = 1, nickel atoms preferentially occupy one in three of the kagome-like layers of the shandite structure. We wish to exploit the Co/Ni contrast  afforded by powder neutron diffraction to characterise the metal atom order in Co3-xNixSn2S2 and for the critical compositions x= 1, 2, investigate its temperature dependence. Although Co/Ni ordering does not enlarge the unit cell, simulations indicate that it introduces new reflections into the neutron diffraction pattern  and alters the relative intensities of reflections arising from the underlying trigonal sub-cell.
DOI: 10.5286/isis.e.rb1510210
title: Novel Mixed Valence Transition-Metal Fluoride Phases

description: Complex transition metal fluorides are of increasing interest to the solid-state chemistry and physics communities due to the diverse range of physical properties they exhibit. In contrast to the analogous oxide phases, complex transition metal fluorides tend to be anion rich (thus favouring lower dimensional crystal structures) and also contain transition metal cations in lower oxidation states than analogous oxides, giving us access to different electronic and magnetic lattices. Recently we have prepared two novel mixed valence transition metal fluoride phases, namely K4Fe3F12 and Ba3Mn3F14 which exhibit unusual complex magnetic behaviour. We propose to collect neutron powder diffraction data from these samples to investigate the complex magnetically ordered structures these phases adopt.
DOI: 10.5286/isis.e.rb1510304
title: Pressure-dependent powder neutron diffraction of the p-orbital molecular magnet, Cs4O6

description: The mixed-valence sesquioxides A4O6 (A = alkali metal) are particularly intriguing molecular materials comprising of non-magnetic (O2)2- and magnetic (O2)- anions. Our recent diffraction work at ISIS has unveiled a very complex structural phase diagram at ambient pressure also characterised by extreme sensitivity to thermal protocols and thermal history of the sample. With the present experiments we will extend our investigations to high pressure and initiate a systematic neutron diffraction study of these systems at elevated pressures in an attempt to investigate the nature of the structural evolution with pressure and compare the structural (andelectronic/magnetic) response with that at ambient pressure.
DOI: 10.5286/isis.e.rb1510491
title: Quantum dynamics in a J_eff=1/2 isotropic triangular-lattice antiferromagnet

description: This proposal is part of our research programme to explore the spin dynamics of strongly-frustrated quantum antiferromagnets. A canonical model system is the spin-1/2 triangular antiferromagnet for which many theoretical predictions such as quantum-fluctuations induced anomalous lineshape broadenings and roton-like minima in the dispersion have not been experimentally explored. In recent powder experiments we found that Ba3CoSb2O9 is a unique realization of such as system with i) a density of states consistent with an anomalous softening at the zone boundary as expected for roton-like minima and ii) strong scattering continuum at high energies indicating quantum dynamics beyond the linear spin-wave approximation. To explore such effects in detail we propose a single crystal experiment to map the excitations in the full Brillouin zone and compare with theories of quantum dynamics.
DOI: 10.5286/isis.e.rb1510549
title: Null Isotope Study of Lithium Borogermanate Glasses

description: Alkali borogermanate glasses are topologically complex, in that [BOn] (n = 3, 4)and [GeOn] (n = 4, 5, 6) polyhedra may all coexist. Equilibrium between these structural units has significant influence on physico-chemical properties such as conductivity and corrosion resistance. In previous work on the potassium system we used neutron diffraction and NMR to show that K preferentially associates with borate units to form [BO4] in preference to [GeO5] or [GeO6], giving an increase in average coordination of B from 3 to 3.8 but of Ge from 4 to only 4.3. We wish to repeat the study with the lithium system where we can take advantage of the opposite signs of the scattering lengths of the Li-6 and Li-7 isotopes to produce samples which show null scattering from Li. This simplifies the problem and, by comparison with samples formed with natural Li we can study the Li environment itself.
DOI: 10.5286/isis.e.rb1510641
title: Tackling antimicrobial resistance: structural study of the Annexin A5/Lipopolysaccharide (LPS) complex

description: Antimicrobial resistance is a global epidemic and has occurred due to a widespread antibiotic overconsumption. Gram negative bacteria, such as P. aeruginosa (leading cause of mortality in cystic fibrosis patients) are of particular concern due to the limited permeability of bacterial cell wall to antibiotic drugs. One promising strategy is to increase the permeability of the bacterial outer membrane prior to antibiotic delivery. Annexin A5 is a calcium-dependent phospholipid binding protein that targets phosphatidylserine (PS) and under certain conditions can destabilize membranes. Recently it has been shown to also bind LPS-containing membranes and here we propose to study the interaction of Annexin A5 with PS and LPS using neutron reflectivity in order to better understand the structural requirements to turn Annexin A5 into a potentially effective antimicrobial therapy agent.
DOI: 10.5286/isis.e.rb1520259
title: Observation of hydrogen dynamics in hydrogen storage materials by in situ muSR measurements

description: This proposal describes an in situ muSR experiment on a hydrogen storage material, MgH2. This is because MgH2 attracts a special attention due to the fact that the hydrogen desorption temperature (Td) is drastically decreased by milling and additives. In order to clarify a key factor to determine Td, we have measured muSR spectra for "as-prepared" MgH2 and "milled with/without additives". We have found that rapid diffusion of liberated hydrogen in MgH2 is essential to accelerate the desorption reaction from the systematic change in the spin-lattice relaxation rate with milling and additives. In order to confirm our finding, however, we need to demonstrate that the muSR parameters changes simultaneously with the hydrogen desorption reaction. For such purpose, we want to measure pressure in the sample cell during the muSR experiment.
DOI: 10.5286/isis.e.rb1610210
title: Low temperature magnetic order and spin dynamics in Ho2Ir2O7

description: Ho2Ir2O7 has a cubic pyrochlore structure. Trigonal crystal fields at both the Ho and Ir sites create Ising-like moments that can order in a non-collinear arrangement with moments along, or perpendicular to, the local [111] directions. Magnetization, heat capacity, and neutron scattering data indicate that Ho2Ir2O7 undergoes a sequence of magnetic transitions associated with the both the Ir and Ho moments. We propose to use muon spectroscopy to study the magnetic order in a polycrystalline sample Ho2Ir2O7 This work will allow us to investigate the ordering and dynamics of both the Ir and Ho moments, as well as the interplay between the two magnetic sub-lattices.
DOI: 10.5286/isis.e.rb1610236
title: Investigation of Li diffusion in Li-ion battery materials by muSR

description: We would like to propose a continuation experiment on Li-ion battery cathode material, Li(Ni,Co)O2. In previous experiments in 2013 and 2014, we attempted muSR technique to  practical cathode sheets of Li-ion battery to observe Li-ion diffusion in Li(Ni,Co)O2. We tried to extract a signal from Li(Ni,Co)O2, although the effect of Al foil in cathode sheets was not completely removed. As a result, we obtained dyanmic signals due to both Li-ion diffusion in Li(Ni,Co)O2 and muon diffusion in Al foil. We estimated Li-ion diffusion coefficient for Li(Ni,Co)O2, of which the composition dependence is comparably different from that measured for powder samples of other typical battery materials. It is important to verify the characteristic behavor for Li(Ni,Co)O2. In addition, this experiment will help for us to confirm that muSR can be applied to in situ measurements of Li-ion battery.
DOI: 10.5286/isis.e.rb1610485
title: Investigation of the reduced dimensionality and magnetic frustration in ACr3As3 (A = K, Rb and Cs)

description: The recently superconductivity in a quasi-one-dimensional (Q1D) crystal structure, A2Cr3As3 (R=K, Rb and Cs), have been intensively investigated both experimentally and theoretically. We have published one musr paper on K2Cr3As3 PRB(2015) and second is in preparation. The new compounds ACr3As3 (A = K, Rb and Cs) remain 1D (Cr3As3)∞ linear chains, and the interchain distance can be tuned by the incorporation of the alkali-metal cations with different sizes. The physical-property indicates a local-moment behaviour (T&gt;60K), and the moments freeze into a cluster spin-glass state below 5~6 K.  No superconductivity was observed in ACr3As3  materials, with increasing the interchain distance, the Cr effective moments increase monotonically. Using the high sensitivity of the ZF-μSR and LF-SR technique, we would like to find the static or dynamic magnetism in these compounds.
DOI: 10.5286/isis.e.rb1610509
title: A study of Line Broadening of the Muonium RF Signal in the Presence of O2 Spin Exchange

description: Considerable work has been carried out at ISIS with the aim of studying muoniated radicals in the gas phase by RF techniques. This has been motivated both by a desire to establish the method, a 'first' for any kind of magnetic resonance, and the unique possibility of measuring muoniated radicals with no nuclear moments in the gas phase. Despite this attention, we have been unable to measure the RF signature of a radical formed in the gas phase. By measuring a model system, this proposal seeks to understand this result. Resonance lines will be measured for Mu formed in N2 gas containing a known O2 impurity concentration. Spin exchange will broaden the lines, and the experimental results will be compared to theoretical predications with the aim of understanding whether relaxation mechanisms have a disproportionate effect on resonance.
DOI: 10.5286/isis.e.rb1620054
title: On the inhomogeneous ground state of the two-dimensional frustrated antiferromagnet a-NaMnO2: a single crystal study

description: The layered NaMnO2 is challenging as it is an experimental realization of a two-dimensional spin-2, spatially anisotropic triangular lattice, where the interplay of temperature and strong conflicting interactions, stimulates a remarkable inhomogeneous magnetic ground state. The proposed neutron diffraction experiment will utilize a single crystal specimen that has recently been grown at Warwick to study how the ground state degeneracy of NaMnO2 is lifted. The unusual short-range order that precedes the low-temperature transformation to an antiferromagnetic state and its coexistence with low-dimensional magnetic correlations will be studied to allow a greater insight on the origin of inhomogeneity. Subsequently, its sensitivity to small perturbations that could favor certain states among the degenerate ground-state manifold, will be investigated by a moderate external magnetic field.
DOI: 10.5286/isis.e.rb1620364
title: Atomistic modeling of temperature-driven structural alterations in a ferroelectric solid solution with a reduced Pb content

description: Ferroelectric materials, mainly Pb-containing, have widespread applications in our modern-day life, primarily used as sensors, actuator and memories. However challenges still remain to understand the structure-property relations at the atomic level, which is crucial in order to develop bespoke materials with improved qualities, and to find Pb-free alternatives to avoid environmental concerns. Here we aim to investigate a reduced Pb-content ferroelectric system (1-x)PbTiO3 -xBi(Mg1/2Ti1/2)O3, which was first reported in 2004 as a promising high-temperature (Tc ~ 700 K) piezoelectric material, through studying their pair distribution function at ambient and non-ambient temperature with a view to establish categorically the behavior of each cation or a preferred chemical order that impacts the properties of the system. We propose to use GEM for this study, which is a dedicated PDF beamline.
DOI: 10.5286/isis.e.rb1620394
title: Mixed alkali environment in chalcohalide glasses for optical applications

description: Heavy alkali halide sulphide and selenide glasses are promising hosts for active and passive optical devices.  Lithium and sodium chalcohalide glasses exhibit high ionic conductivity and can be used for battery applications.  The atomic structure of these glasses is extensively studied using spectroscopic techniques but the diffraction studies are rare.  Recently, we have used a combination of neutron and high-energy x-ray diffraction to unveil the short and intermediate range order in NaCl-Ga2S3-GeS2 glasses.  Surprisingly, the sodium tetrahedral environment in these glasses appears to be mixed with Na-Cl and Na-S neighbours.  This structural information has never mentioned in available literature and allows a new insight into atomic structure of these practically important chalcohalide glasses.  Consequently, we aim to investigate whether the mixed alkali environment exist for K and Rb
DOI: 10.5286/isis.e.rb1620459
title: Investigation of complex magnetic structure and the role of frustration using neutron diffraction study in CeRh1-xPdxSn

description: The quasi-kagome Kondo lattice CeRhSn exhibits intrinsic quantum criticality induced by geometrical frustration. Divergent Grüneisen ratios provide evidence for a zero-field QCP. The anisotropy of thermal expansion, which only displays quantum critical behavior along a-axis and not along the c-axis, indicates that geometrical frustration drives quantum criticality in this system.. Our recent study of CeRh1-xPdxSn series reveals magnetic transitions for x ≥ 0.4. The spin-flop behaviour in the magnetization curve supports the AFM ordered state. We have found that the NFL state of CeRhSn is easily transformed to an AFM ordered state with Pd doping. Our aim is to investigate complex magnetic structure and role of frustration by means of neutron diffraction study which is very important to develop new theoretical model for geometrical frustration induced quantum phase transitions.
DOI: 10.5286/isis.e.rb1670543
title: mSR Study of Non-Magnetic Anion Based Organic Superconductor l-(BETS)2GaCl4
DOI: 10.5286/isis.e.rb1670569
title: Spin dynamics in the S=1/2 zigzag spin chain magnets K2CuCl2SO4 and Na2CuCl2SO4

description: We have recently succeeded to synthesize pure-phase of K2CuCl2SO4 and Na2CuCl2SO4. In addition, we succeeded to grow the large single crystals (~ 10×10×10 mm3). K2CuCl2SO4 is a good candidate compound for the S = 1/2 zigzag spin chain system. Moreover, our experimental results are indicating that K2CuCl2SO4 is only sample which can be investigate the spin nematic state by using muSR and inelastic neutron scattering method. On the other hand, the development of short-range correlations at around 10 K and the long-range ordering at 0.5 K was observed in Na2CuCl2SO4.  Firstly, we should investigate the spin dynamics of K2CuCl2SO4 and Na2CuCl2SO4 in zero field (and weak LF). In this experiment, we expect to observe the characteristic spin dynamics of a vector chiral state in K2CuCl2SO4 and an unconventional spin dynamics between 0.5 K and 10 K in Na2CuCl2SO4.
DOI: 10.5286/isis.e.rb1700041
title: Neutron Measurements with a Telescope Proton Recoil Spectrometer on ChipIR

description: A TPR spectrometer has been designed and realized for the new ChipIR beamline. Here the YAP crystals (1 and 0.1 thick) will be used in coincidence with silicon detectors in ΔE-E configuration.The fast neutron spectrum (E &gt; 10 MeV) is a critical feature for a beamline designed for chip irradiation experiments (such as ChipIR). The spectrum of ChipIR has been calculated with Monte Carlo simulations. Direct measurements of the spectrum are needed for the characterization of the neutron flux, to benchmark the simulations, and for a better understanding of the ChipIR fast neutron beam. These measurements can be carried out with a TPR.
DOI: 10.5286/isis.e.rb1710020
title: Symmetry and Size Effects in the Dynamics of Adsorbed PAHs: Fluoranthene on Graphite

description: Self-assembled monolayers are employed in the fabrication of organic transistors and organic-electronic devices. Polycyclic aromatic hydrocarbons (PAHs), a class of organic precursors made by multiply fused aromatic rings, have been particularly promising for optoelectronics applications. Relatively unexplored is the dynamics of adsorbed PAHs, although the diffusional properties of organic precursors are central in the self-assembly process. The experiments we propose aim to elucidate the dynamics of fluoranthene (a common PAH) on graphite. Previous studies on benzene and pyrene have allowed us to postulate a correlation between molecular size and diffusion rate of PAHs. Our goal now is to verify if the presence of a five-carbon ring in fluoranthene will influence the dynamics of this molecule by making the surface diffusion faster than predicted by the simple molecular-size rule.
DOI: 10.5286/isis.e.rb1710037
title: Low temperature high magnetic field Neutron diffraction studies of re-entrant charge ordering transition in La5/8-yPryCa3/8MnO3 (y=0.45)

description: Our aim is to investigate the chemical and magnetic structure of the charge ordered (CO) AFM and charge disordered FM phases of  La5/8-yPryCa3/8MnO3 down to 2 K and study the variation of their relative phase fraction under zero field cool and field cooled conditions. The magnetic structure changes during this re-entrant (CO) transition are missing in the literature. The H-T phase diagram constructed using XRD studies shows that the field requirement to transform the AFM to FM first decreases with decreasing temperature down to 39 K and then increases with further decreasing temperature down to 2 K. The origin of this phase diagram actually lies into this re-entrant CO behaviour. Our preliminary XRD study demands some strong proof to conclusively present the results. The melting of CO phase will be studied studied by performing the neutron diffraction under external magnetic field.
DOI: 10.5286/isis.e.rb1710071
title: Probing One-Dimensional Magnetic Order in Tb(HCO2)3 by muSR

description: Low dimensional magnetism provides a crucial playground for the discovery and exploitation of unconventional magnetic properties. With in this context the study of 1D magnetic systems is arguably the topic of strongest scientific interest. The experimental realisation of some of the key theoretical models is still a fundamental challenge and the area where this experiment will make a contribution. Coordination frameworks, including dense metal-organic frameworks (MOF's) are natural platforms in which to study low dimensional magnetism because they tend to form very anisotropic structures. In this experiment we propose to investigate the properties of one of these systems, Tb(HCO2)3, using muSR. This material realises the model for triangular Ising antiferromagnet for the first time. We would like to investigate the properties of this phase as a function of temperature and magnetic field.