cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1510525
title: Superconductivity in Noncentrosymmetric Iridium Silicide Li2IrSi3

description: Li2IrSi3 crystallizes to a novel trigonal structure with the space group P31c, which consists of an alternate stacking of planar silicon kagome planes and Li and Ir planes. The structure is weakly noncentrosymmetric owing to the displacement of kagome planes along the c-axis and the staggered rotation of silicon triangles in the kagome planes. Superconductivity at 3.8 K was discovered in Li2IrSi3. Weakened inversion symmetry breaking, together with the increased electronic DOS at the Fermi level, plays a key role in the superconductivity of Li2IrSi3. We aim to perform the muon-spin rotation (µSR) study, both transverse field (TF) and zero field (ZF) to investigate microscopic superconducting properties of Li2IrSi3. TF µSR provides measurements for superconducting Gap structure. ZF µSR is important to know time reversal symmetry of the superconducting state is broken or preserved.
DOI: 10.5286/isis.e.rb1520419
title: The Effect of the Polar Interfaces on the Exchange Bias in NiO/EuO(001) Heterostructure

description: The study of the interfaces of multi-layer heterostructures have attracted a great attention as they exhibit new properties at the interface, while leaving the bulk layers unaffected. Various changes in magnetism, electrical conductivity, superconductivity and the formation of two dimensional electron gas (2DEG) have been reported in different oxide structures. Therefore, they are potential materials for different technological applications, such as in spintronics. We propose to study the effect of polar interfaces on the exchange bias and the creation of 2DEG in NiO/EuO structure using off-specular polarised neutron reflectivity.
DOI: 10.5286/isis.e.rb1610019
title: Magnetic structure of Cr2GaN

description: The Mn+1AXn phases, crystalized in hexagonal P63/mmc, have attracted considerable interest for its metallic properties and mechanic properties. In 2013, Liu et al reported that a spin-density-wave (SDW) transition has been found in Cr2GaN at TN = 170 K. It is also noticed that the transport properties of Cr2GaN is very similar to the parent compound of iron-based superconductors, and the formation of the SDW state is also theoretically interpreted in terms of the nesting of Fermi surfaces of the two-dimensional-like electronic structure. The significantly correlated nature of the d band electrons in Cr makes the magnetic coupling and ferromagnetic/antiferromagnetic ordering are very sensitive to other elements in MAX compounds. Thus it would be very interesting to determine the magnetic structure of the nitride Cr2GaN.
DOI: 10.5286/isis.e.rb1610035
title: High pressure charge and magnetic transitions in PbCrO3

description: The high pressure perovskite PbCrO3 has been known since the 1960s but the electronic properties were controversial. The average structure is a cubic Pm-3m perovskite but a recent study revealed a charge ordering as Pb2+0.5Pb4+0.5Cr3+O3 with a ~3 x 3 x 3 Pb2+/Pb4+ ordered superstructure over small correlation lengths. A large pressure-induced volume collapse of 9.8% at ~2 GPa is due to a insulator-metal transition accompanying the charge transfer to high pressure configuration Pb2+Cr4+O3. Neutron diffraction is required to study structural and magnetic changes accompanying the unusual insulator to metal change in PbCrO3. Neutrons will show how TN (= 240 K at ambient P) changes with pressure, whether the G-type antiferromagnetism is suppressed at the transition, and whether the length scale for 3-fold local superstructure changes with pressure approaching the transition.
DOI: 10.5286/isis.e.rb1610093
title: High pressure behaviour of ammonium carbamate

description: A number of compounds crystallise in the NH3-H2O-CO2 ternary system, including ammonium carbonates and carbamates, these being closely related to the water-deficient compound urea. NH3, H2O and CO2 are abundant in interstellar and planetary ices so we expect carbonates and carbamates to occur in the interiors of icy planetary bodies.Our objective is to obtain high-pressure information on the structure and properties of ternary NH3-H2O-H2O compounds to provide the basis of accurate planetary interior models. The proposed experiment complements recent ab initio calculations that show extreme elastic anisotropy (specifically, negative linear compressibility).Here we propose to compress deuterated ammonium carbamate to order 10 GPa using the Paris-Edinburgh press on PEARL, which we hope will confirm our DFT calculations and reveal the existence of any high-pressure polymorphs.
DOI: 10.5286/isis.e.rb1610123
title: LOW DIMENSIONAL NETWORKS UNDER PRESSURE. IN-SITU DIFFRACTION MEASUREMENTS OF CARBONATE GLASSES.

description: Carbonate liquids are characterised by low temperature and low viscosity and play an important role in molten carbonate fuel cells, battery electrolytes and, surprisingly, in volcanic processes. Indeed they are important agents of element transfer in the deep Earth interior. Despite their unique role determined by structure-related properties little is known about the carbonate liquid structure. A recent study has shown that the liquid structure comprises chains of linked, triangular carbonate anions which form a low-dimensional network. This network is temperature dependent and chains decrease in length with temperature. The aim of this work is to determine what happens to the carbonate chains when pressure is applied. The experiment will comprise a set of diffraction measurements, combined computer simulation, and will to explore the high pressure behaviour of these exotic glasses.
DOI: 10.5286/isis.e.rb1610527
title: Dirac Point and Topological Triplon Bands in the Shastry-Sutherland Material SrCu2(BO3)2

description: SrCu$_2$(BO$_3$)$_2$ (SCBO) is a very much studied quantum magnet that is most well known for its ground state of coupled singlets and multiple magnetization plateaux. Recently, a group of theorists proposed that in the little studied low field regime, SCBO is a magnetic relative of the celebrated topological insulators. To our knowledge, this is the first proposed case of a topological band structure in a magnetic insulating material. Our experimental proposal is intended to make progress towards establishing whether this theoretical picture is correct. The first part of the experiment is to use inelastic neutron scattering to investigate the magnetic excitations in small field where we expect to observe a band gap opening in a field and closing again at a Dirac point. In the second part a simultaneous Raman experiment will correlate the bulk Raman signal with the neutron measurements.
DOI: 10.5286/isis.e.rb1661004
title: Characterization of Indo-Persian swords of the Wallace Collection
DOI: 10.5286/isis.e.rb1720066
title: INS analysis of industrially relevant small pore zeolites

description: NOx emissions from the energy and transport sectors represent a major hazard to human health and this has been the focus of significant industrial and academic research.  One important process in emissions control from vehicles is the selective catalytic reduction reaction (SCR), in which a reductant such as ammonia is injected into the exhaust to reduce the NO and NO2 (NOx) to harmless nitrogen.  Copper combined with small pore zeolite materials has been shown to be very effective, but there is much still to understand about the mechanism.  With greater understanding it is hoped that more effective catalysts can be designed.  Here we will use TOSCA to characterise adsorbed ammonium and nitrate species in the zeolite structure.
DOI: 10.5286/isis.e.rb1720259
title: A MuSR study of the superconductivity in ACa2Fe4As4F2 (A = K, Rb, Cs)

description: The iron pnictide (Fe-Pn) superconductors were the second family of high temperature superconductors to be discovered and have a number of different crystal structures. We propose to perform muon spectroscopy (MuSR) measurements on ACa2Fe4As4F2 (A = K, Rb, Cs), which belong to a new family of Fe-Pn high temperature superconductors, with a different crystal structure. We aim to characterize the superconductivity of this family both by probing for  broken time reversal symmetry and by determining the superconducting gap structure. MuSR is a powerful technique for determining the superconducting gap symmetry, since the penetration depth can be obtained from probing the internal field distribution. This is important work for the study of iron based superconductivity, since it is currently of great interest whether all Fe-Pn families share a common gap symmetry and pairing mechanism.
DOI: 10.5286/isis.e.rb1720280
title: Revealing deformation mechanisms in a novel eutectic high entropy alloy at cryogenic to elevated temperatures

description: In recent years, an exciting new type of engineering materials called high entropy alloys (HEAs) has received widespread attention. The excellent microstructural stability of these materials makes them interesting candidates for high temperature structural applications. A novel type of HEAs with eutectic microstructure, with good castability allowing easy production in bulk form, have shown an extraordinary combination of strength and ductility at temperatures ranging from cryogenic to 700°C. By the proposed experiments we aim to unravel the reason for this remarkable behaviour by employing in-situ neutron scattering experiments to understand the deformation mechanisms over the entire temperature regime.
DOI: 10.5286/isis.e.rb1720372
title: Spin dynamics in the Tomonaga-Luttinger Liquid (TLL) State appeared in the Superoxide

description: The TLL phase is a quantum spin condensed state in the one-dimensional system. In the case of DIMPY system which is a quasi-one-dimensional organic magnet, the TLL phase is induced by the magnetic field forming a sea of the singlet spin state with some excited triplet spins. The µSR measurement successfully picks up the spin-relaxation behavior in the TLL phase in this system. Our target system to study the TLL state is the CsO2 which is one of superoxides series which we are currently working to investigate magnetic properties of magnetic moment on the O2 dumbbell. It is recently reported from NMR measurement that the TLL phase is realized in this system also below about 30 K down to TN~9 K. Since the µSR study in the DIMPY system is well working on the TLL phase, we follow the similar measurement on CsO2.  We try to achieve more accurate information on the TLL phase rather than NMR.
DOI: 10.5286/isis.e.rb1768020
title: Effects of Ionic liquids on the Dynamical and Phase Behaviour of Phospholipid Membrane

description: Ionic liquids (ILs) have attracted considerable interest as a promising green substitute for organic solvents. Although, toxicity of some ILs is a cause for concern, recent studies have shown that the toxic interactions of ILs toward biological systems can be quite useful, particularly for antimicrobial applications.  1-n- alkyl-3-methylimidazolium (Cnmim), a popular class of ILs, has been shown to be toxic toward several classes of aquatic species and organisms. Interactions of ILs with the cellular membrane play a major role towards toxicity as well as antimicrobial applications. The fundamental mechanisms underlying the interactions between ILs and cells are not well studied nor completely understood. Our aim is to investigate effects of Cnmim( n=4, 8, 10) on the dynamical and phase behaviour of phospholipid membrane and its correlation with the cation chain length of the ILs.
DOI: 10.5286/isis.e.rb1768023
title: Study of Local Magnetism of Magnetic Dopants in Topological Insulator Bi2Se3 by MUSR

description: Topological insulators (TIs), which are insulating in bulk and conducting on surface due to a protected time-reversal symmetry (TRS), have become of great interest recently. The TRS can be broken by elemental magnetic doping. 3D TI Bi2Se3 is one such example. One attractive direction could be the use of nanostructures, wherein the surface-to-volume ratio is high. Recently, we synthesized Co- and Dy-doped Bi2Se3 hexagonal nanoplates (NP's). Magnetization measurements indicated the occurrence of a ferromagnetic phase at very low temperatures (T), while the NP's are diamagnetic or paramagnetic otherwise. Weak Co and strong Dy moments were found to accompany this behaviour. Thus, there is an unsystematic magnetic behaviour of the NPs. We propose measurements of local magnetic properties using MUSR at varying T and magnetic field to gain further insight into the problem.
DOI: 10.5286/isis.e.rb1810302
title: Magnetic excitations in the magnetoelectric quantum spin chain Rb2Cu2Mo3O12

description: All of the known mechanisms for magnetically-driven ferroelectricity require a form of magnetic long range order (LRO). Recently however, a new mechanism has been proposed where a fluctuating vector chiral order of spins induces a time-averaged bulk ferroelectric moment in the absence of LRO. From theory it is suspected such a state may exist in a S=1/2 XXZ spin chain, of which our subject material Rb2Cu2Mo3O12 is a promising realisation. Using LET we wish to explore the magnetic excitations of Rb2Cu2Mo3O12, both inside the purported vector chiral state for which T&lt;1.7 K and H&lt;2 T, and at higher field where a dielectric transition occurs at ~2 T and 100 mK to a likely LRO phase. The results of this experiment are needed to clarify the forms of magnetoelectric coupling across the phase diagram of this material, which may include an entirely new form of magnetoelectric coupling.
DOI: 10.5286/isis.e.rb1810487
title: Investigation of Magnetic Ground State of Hexagonal Rare-Earth Ferrites by µSR

description: This experiment is focused on exploring and harnessing magnetic ground state of the multiferroic materials, with particular emphasis on the hexagonal (h), rare-earth ferrites (RFeO3). The Fe ion sitting at the in-plane triangular noncollinear lattice of h-RFeO3 crystal promotes the instability of the magnetic structure and leads to complex magnetic phase diagram. The magnetic properties of these materials can be tuned by controlling the frustration parameter through a careful selection of materials. We will systematically study families of multiferroic materials in which the localized moments reside on triangular sublattice configurations.
DOI: 10.5286/isis.e.rb1820590
title: Quantum tunnelling of muonium via radical states in molecular solids

description: The extreme quantum nature of muons and muonium in condensed matter is the result of having a mass that is nine times lighter than that of a hydrogen atom.  While this quantum nature may often be masked by thermal excitations, at low temperatures its dramatic effects can become more apparent.  This was clearly demonstrated in solid state benzene ALC spectra below 120 K, where we have observed both intramolecular and intermolecular multisite quantum tunnelling of radical states.  In this proposal we aim to use molecular engineering to control the sites available to form quantum tunneling states and we will use low temperature solid state ALC spectroscopy to confirm the effect of the different modifications we have made to our reference molecule. The modifications will take the form of selective substitutions of the benzene molecule and four different examples will be studied.
DOI: 10.5286/isis.e.rb1900047
title: IMAT commissioning: Detailed characterization of vacuum sealed neutron sensitive microchannel plate imagers

description: Neutron sensitive Microchannel Plates (MCP) have been fabricated and tested in a number of imaging configurations over the past decade, however to date the majority of these systems rely on mounting the MCPs in a vacuum chamber that must be actively pumped. These systems are bulky, difficult to maintain, and the MCPs are difficult to properly process for long lifetime and minimum image burn-in. We have recently built several sealed vacuum tubes incorporating neutron MCPs using MCP processing techniques originally developed for long-life image intensifiers. In this project we will fully characterize two neutron cameras for imaging performance and burn-in. Successful demonstration of these cameras will enable widespread adoption of this technology for neutron radiography, providing the community with improved sensitivity and ease of use.
DOI: 10.5286/isis.e.rb1320382
title: Comparison of H and D diffusion rates in micron-scale palladium

description: There is currently considerable interest in the use of micron scale palladium powder for the separation of hydrogen isotopes ¿ e.g. tritium extraction in connection with fuel for fusion. The rate of isotope exchange is determined by three main factors: The time for the gas to percolate around the particles, the permeation rate through the surface of the particles and the diffusion rate within the particles. We (Salford University in collaboration with AWE) are in the process of developing a model incorporating all three of these contributions, using data from permeation and gravimetric absorption measurements to parameterise the first two contributions and are seeking to obtain reliable data for the isotope dependent bulk diffusion rates, for which QENS is the ideal probe.
DOI: 10.5286/isis.e.rb1410350
title: Further SANS contrast measurements on important protein/DNA interactions from RCaH

description: This proposal is to perform further SANS contrast measurements on three protein/DNA interactions currently worked on at the Research Complex at Harwell. This is part of an ongoing productive relationship between the two facilities, coordinated by Dr. David Scott of the University of Nottingham funded by ISIS to sited in the RCaH 2 days a week.The systems understudy all form part of crystallographic studies as part of an MRC programme grant to Prof. Simon Phillips, the RCaH Director, and all are important in the fundamental processes of DNA repair, recombination and replication. Preliminary data is available from SAXS and analytical ultracentrifugation measurements showing that the systems are stable in D2O and monodisperse. Preliminary SANS data through SANSexpresses has shown that suitable concentration ranges are attainable for further SANS measurements.
DOI: 10.5286/isis.e.rb1410391
title: Thermal and spin currents: making them work for us

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. In order to assess the feasibility of the spin Seebeck effect as a route to harvest waste energy we propose investigating the voltage generated for a variety of contacts designed to minimise cost and maximise efficiency (i.e., the spin Hall angle). Spin polarised neutron reflectivity will provide us with complementary measurements that enable determination of the spin polarisation of the film as well as surface sensitive magnetic ordering and disorder at the interface. This is especially important as the influence of the interface on the collection of the spin polarised current due to theinverse spin Hall effect is still not well understood.
DOI: 10.5286/isis.e.rb1510033
title: µSR study of mixed intercalated phases NaxLi6-xC60

description: Alkali-cluster intercalated fullerides (LixC60, NaxC60) proved to be suitable materials for solid state hydrogen storage. In these compounds the hydrogen is chemically absorbed on the fullerene molecule while the intercalated cluster is able to dissociate the hydrogen molecule at moderate temperature and pressure. Here we intend to study the hydrogen binding mechanisms in the new class of mixed sodium and lithium fullerides (Na_{x}Li_{6-x}C_{60}).  Thanks to the capability of muons to form a light isotope of hydrogen (muonium, Mu), we will be able to investigate the chemical interactions of Mu with our systems, comparing the results with those obtained with the pure Li and Na intercalated fullerene.
DOI: 10.5286/isis.e.rb1510047
title: Self-assembly of detergent molecules below ambient temperature: SANS to determine the micellar structures from model binary mixtures

description: Although surfactant detergency is well understood above 30 C, actions of surfactants below 30 C are not well established. In the era of energy saving and environment caring, we must understand how to optimise detergency in what are increasingly hostile environments. Existing surfactant mixing theories such as regular solution theory are not validated at low temperatures, and other factors such as being closer to the solubility limit of the surfactants, and perhaps proximate to phase boundaries also need to be taken into account. It is hence vital that industry is supported with both data and a thermodynamic description of the behaviour of detergent components at ambient and below ambient temperatures. This work proposes to study how model surfactants behave in model binary mixtures below ambient temperatures using SANS.
DOI: 10.5286/isis.e.rb1510091
title: Pressure-induced O(2) quantum phase transition in a quantum antiferromagnet

description: Quantum phase transitions (QPT) continue to attract the attention of experimentalists and theorists alike. Experiments on quantum magnets have been crucial to understand their underlying physics. Famous examples include the Bose-Einstein condensation of magnons (which spontaneously breaks O(2) or the isomorphic U(1) symmetry, dynamical critical exponent z = 2), the Ising chain in transverse fields (emergent E8 symmetry), and the pressure-induced QPT in TlCuCl3 (O(3), z = 1) which displays a longitudinal Higgs excitation. Here we propose to perform time-of-flight spectroscopy on what we believe is the first realization of a 3D O(2)-breaking z = 1 QPT in the material dichloro-tetrakis-thiourea-nickel (DTN), in which we have recently discovered a pressure-induced quantum critical point (QCP) at around 1 kbar.
DOI: 10.5286/isis.e.rb1510410
title: Kinetics and Structure of Butanone Hydrogenation in the Presence of a Water Solvent

description: Over 75% of all chemicals and fuels require the use of a catalyst in their generation. However, despite their ubiquity, very little is known on the atomic and molecular processes occurring on the microscopic scale, particularly in the case of heterogeneous catalysts where the reactions occur in nanoscopic pores of the material. Our previous studies showed that it was possible, using total neutron scattering, to ascertain the kinetics of a model catalytic reaction (that of benzene hydrogenation), and subsequent experiments have gone on to look at the hydrogenation of toluene and phenylacetylene.  However, all these reactions were studied neat - that is, the reactant also acted as its own solvent. Here, we propose to study the hydrogenation of butanone to butanol in the presence of water, in order to reveal the kinetics and structure in the presence of a solvent.
DOI: 10.5286/isis.e.rb1510523
title: Characterising the magnetic structure of Pd3Fe under pressure

description: Pd-Fe alloys are of interest due to the unusual interplay between the magnetic and mechanical properties they display. Examples include shape-memory effects in Fe-rich alloys, and the pressure induced zero thermal expansion (`Invar' behaviour) of Pd-rich alloys. Previous work has shown that Pd3Fe undergoes a large volume collapse under a pressure of 12GPa, with a loss of magnetic order. At this pressure the sample also displays almost zero thermal expansion up to 550K. From subsequent simulations and inelastic studies, it is not clear whether the sample becomes magnetically spin-disordered or geometrically frustrated (non-collinear). This study proposes a 3 day single-crystal neutron diffraction study on WISH in order to characterise the magnetic structure of the sample in this high pressure phase. This study hopes to provide insight into the nature of `Invar' behaviour in binary alloys.