cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1510145
title: Determination of the on-top vibrational mode of the surface hydride in PdH.

description: Finely divided supported palladium particles are used as catalysts in many technical processes. Using MAPS we have recently investigated the interaction of hydrogen with the Lindlar catalyst (PdPb/CaCO3) and commercial carbon supported Pd-based catalysts used for the selective hydrogenation of nitro-arenes to amino-arenes. In addition to the presence of the modes of the (expected) hydrogen-in-metal system β-PdH near 500 cm-1, we observed an additional very weak mode at ~2100 cm-1 on Pd(20 wt%)/C and Pd black. In view of their commercial importance, palladium hydrogenation catalysts have been extensively studied for more than 50 years, so the detection of a new catalytic site is very significant. Our experience is that MERLIN has an approximately tenfold advantage in signal-to-noise ratio over MAPS and we wish to use the greater sensitivity of MERLIN to confirm this novel result.
DOI: 10.5286/isis.e.rb1510222
title: Local cation ordering in bismuth yttrium ytterbium oxide solid electrolytes

description: Solid electrolytes based on Bi2O3 exhibit high conductivity at intermediate temperatures (300-600 deg C) and recent research has revealed the true potential of these materials in intermediate temperature solid oxide fuel cells (IT-SOFCs). There has been much concern about long term stability of bismuth oxide based fluorites, with many systems showing ageing effects that reduce conductivity. Partial double substitution of bismuth by can in some cases lead to greater stability. In the present work we seek to examine possible local cation ordering and its influence on oxide ion distribution and conductivity in the double substituted bismuth oxide fluorite Bi3Y0.5Yb0.5O6 using Reverse Monte Carlo combined analysis of total neutron and X-ray scattering data.
DOI: 10.5286/isis.e.rb1510428
title: Magnetic excitations in the layered honeycomb alpha-RuCl3

description: This proposal is part of our research programme to explore novel phases in correlated electron systems with strong spin-orbit interaction. Here we aim to probe the spin dynamics in the layered honeycomb magnet alpha-RuCl3. The crystal structure is very close to ideal conditions (near cubic crystal field at Ru sites and near 90 deg Ru-Cl-Ru bonds) proposed theoretically to realize a canonical quantum frustrated system, the Kitaev model on the honeycomb lattice. Here all nearest neighbour bonds are of Ising character, but the three bonds that meet at each site have orthogonal Ising directions, leading to strong frustration effects. This proposal builds upon our successful study using neutron diffraction and inelastic scattering, and resonant x-ray diffraction of the magnetism in the honeycomb iridates (Na/Li)2IrO3 and Li2IrO3 polytypes with three-dimensional honeycomb structures.
DOI: 10.5286/isis.e.rb1510512
title: Dynamic Surface excess concentration of pH-responsive chelating surfactants

description: This study will examine a process of slow dynamic change in surface excess of a unique pH-responsive chelating surfactant at the air/liquid interface that occurs over a period of hours. Our earlier, preliminary studies of this phenomenon are focused on equilibrium conditions and to our knowledge, such slow equilibration processes has never been reported for surfactant systems before and the proposed study is therefore of fundamental importance. The specific surfactant is also of direct interest in cleaning contamination of heavy metals and mineral processing. Studying dynamics at the air/water interface is challenging and we need fast measurements: the INTER reflectometer is best suited for these experiments. The thickness of the surfactant layers also provides understanding of the changes at the air/liquid interface and that information is uniquely determined by reflection measurements.
DOI: 10.5286/isis.e.rb1510522
title: An Investigation of Magnetic Transitions in NdMn1-xCoxAsO0.95F0.05 (x = 0.03, 0.06, 0.09, 0.12, 0.15)

description: We have recently reported colossal magnetoresistance (CMR) in NdMnAsO0.95F0.05. The CMR in NdMnAsO1-xFx arises due to competition between a strongly correlated antiferromagnetic insulating phase and a paramagnetic semiconductor with field. In order to further investigate the CMR in NdMnAsO0.95F0.05 we have synthesised samples NdMn1-xCoxAsO0.95F0.05 (x = 0.00, 0.03, 0.06, 0.09, 0.12 and 0.15). Magnetoresistivity results show that the low temperature CMR is quickly reduced with increasing Co doping. Susceptibility and resistivity measurements suggest a ferromagnetic transition occurs at Tc = 22 K, 130 K and 155 K for x = 0.09, 0.12 and 0.15 respectively. NdMnAsO0.95F0.05 is antiferromagnetic with a transition temperature TMn = 356 K. In this experiment we plan to investigate the magnetic phase diagram of electron doped NdMn1-xCoxAsO0.95F0.05 (x = 0.03, 0.06, 0.09, 0.12 and 0.15).
DOI: 10.5286/isis.e.rb1510533
title: Structural and Magnetic Characterisation of New Polar Oxides with Weak Ferromagnetism above 300 K.

description: The synthesis of a phase combining electrical polarisation P and spontaneous magnetisation M is hard because of the distinct electronic structure requirements for the main mechanisms producing each property e.g., the closed-shell Ti and Pb cations which produce polarisation in the ferroelectric perovskite oxide PbZr1-xTixO3 do not have the unpaired electrons needed for magnetisation. It is technologically important to efficiently combine these two long-range orders: multiferroic or magnetoelectric information storage offers the possibility to overcome the drawbacks of ferroelectric memory (slow writing) and magnetic random access memory (high power density) and opens the possibility of four state memory with reduced energy consumption. In the experiments outlined below we propose to characterise the nuclear and magnetic structures of three new polar oxides
DOI: 10.5286/isis.e.rb1510554
title: Investigation of local structure and vacancy ordering in Ca(Ti,Fe,Mn)O3 perovskites

description: The CaTiO3 based perovskites exhibit mixed oxide-ion and electronic conductivity and have potential for use in ceramic membrane reactors. To bring the membranes closer to utilization it is necessary to increase the oxide-ion conductivity.  The ion conduction is mainly governed by the concentration and mobility of oxygen vacancies, and it is thus of crucial importance to gain insight to the structural properties of the materials. The goal of the proposed experiment is to gain insight to details of the structure with respect to oxygen coordination and vacancy ordering in a series of Ca(Ti,FeMn)O3 perovskites with different stoichiometry from neutron scattering experiments using the pair distribution function (PDF) method. The results will be combined with already obtained in-situ synchrotron X-ray diffraction data.
DOI: 10.5286/isis.e.rb1510561
title: Characterisation of new oxide nanocomposites with enhanced ionic conductivity for application as SOFC cathodes

description: A major barrier to widespread use of solid oxide fuel is the high operating temperature required due to the need for sufficient oxide ion diffusion through the cathode (which must also be a good electrical conductor). Improvement of the ionic conduction properties of mixed electronic-ionic conducting oxides is therefore critically important to the development of this technology. We have previously shown that the introduction of a second-row transition metal (Mo6+) on to the B-site of the cubic perovskite; (BSCF) ¿ a well known cathode material ¿ drives the formation of an endotaxial nano-composite composed of distinct single perovskite (SP) and double perovskite (DP) nano-regions, and that the resulting cathode performance is superior to that expected from the two phases in isolation due to high ionic conductivity at the interfaces here we study related systems.
DOI: 10.5286/isis.e.rb1600014
title: Studying the phase diagram of Sr2-xBaxRuO4 by muSR
DOI: 10.5286/isis.e.rb1610056
title: Spin dynamics of the triangular quantum spin liquid candidate: YbMgGaO4

description: A new rare-earth triangular quantum spin liquid (QSL) candidate, YbMgGaO4, has an odd number of electrons per unit cell and spin-orbit entangled effective spin-1/2 (Yb3+). Recently, we have, for the first time, successfully synthesized powder samples and grown high-quality single crystals. Our early studies on magnetic property, heat capacity, and electron spin resonance characterizations have been reported. The measurements consistently and clearly suggested that YbMgGaO4 is a potential QSL with a spinon Fermi surface. Further sensitive and unique measurements, such as μSR and inelastic neutron scattering, are highly required to confirm the QSL ground state, explore and characterize the novel low-energy spin excitations at extremely low temperatures.
DOI: 10.5286/isis.e.rb1610066
title: Probing Unconventional Spin Configurations in Molecular Interfaces

description: Only a few elements are ferromagnetic and the most common are iron, cobalt and nickel.  These elements satisfy a condition, called the Stoner criterion, which determines whether materials are ferromagnetic.  Recently, a different class of ferromagnetic materials based on alternating ultrathin layers of carbon-60 (C60, also called Buckminster-fullerenes or Buckyballs) and non-magnetic metals (e.g. copper or Cu), have exhibited the signatures of ferromagnetism.  This development may lead to entirely new ways of understanding magnetic ordering and use of magnetic materials in information technology.  The magnetism is associated with the number of interfaces of C60 and Cu, and key issue in understanding the origin of this unusual ferromagnetism is how the ferromagnetism decays away from the interfaces.  Neutron scattering is the ideal tool to answer this intriguing question.
DOI: 10.5286/isis.e.rb1610208
title: Investigating the surface structure and composition of binary ionic liquid mixtures

description: The structure of ionic liquid (IL)-gas interfaces is currently a hot topic in the field and our understanding of pure ILs is improving. However, very little is known about the surface structure and dynamics of mixtures of ILs. In recent work, which we plan to publish soon, we have used neutron reflectometry (NR) to investigate the ILs [C2MIM][Tf2N] and [C12MIM][Tf2N] and have found significant surface ordering in [C12MIM][Tf2N]. In addition, we have preliminary evidence, from NR experiments, of surface enrichment of the [C12MIM]+ ions in a mixture of these two ILs containing 24 mol % [C12MIM][Tf2N]. This proposal aims to investigate the effects of composition on the surface structure of these IL mixtures by measuring the reflectivity of two additional compositions containing 8 and 63 mol % [C12MIM][Tf2N]. This is crucial for our understanding of the gas-liquid interface in this system.
DOI: 10.5286/isis.e.rb1610432
title: Surface composition in the physical developer process for latent fingerprint visualization

description: Physical developer (PD) is a latent fingerprint development technique that is highly effective on paper and related surfaces, notably banknotes. The process exploits a redox reaction in which Ag(I) ions in solution are reduced by Fe(II), resulting in deposition of metallic silver on fingerprint residue on the surface. The standard formulation includes a cationic surfactant, whose presence is critical to formulation stability and efficacy, but whose role is poorly understood. By analogy with additives used in electrodeposition processes, surfactant adsorption can be expected to play a significant role. Here, we seek to determine the extent and composition of the surfactant layer on a silver surface using specular neutron reflectivity. Contrast variation of both solvent and surfactant will be exploited. The outcomes will guide optimization of the PD and derivative processes.
DOI: 10.5286/isis.e.rb1610479
title: Is Zeolite Deactivation Through Pore Blocking?

description: Zeolites are porous framework materials that have active catalytic sites inside narrow channels. Unwanted  reactions create coke in the pores which may block access to the active sites. We want to use quasielastic neutron scattering measurements to determine how a model reactant moves in pores with different amounts of coke. This will demonstrate how coke affects the access of the reactant to the active sites and help in designing more robust catalysts for cleaner fuel production.
DOI: 10.5286/isis.e.rb1610490
title: Superconductivity and itinerant ferromagnetism in d-band metal Y9Co7: A muon spin relaxation study

description: The understanding of the pairing mechanism in unconventional superconductors is a major theoretical challenge. Recent results [PRB 91, 235314 (2015)] designate a local concurrence of itinerant ferromagnetism and bulk superconductivity in Y9Co7 below 2.95 K, as conflicting to a preceding belief that superconductivity occurs in the paramagnetic phase embedded in a principally normal magnetic surroundings. Since the clean-limit condition is satisfied for a pure sample of Y9Co7, the interrogation whether magnetic fluctuations contribute in the formation of Cooper pairs in this sole d-band ferromagnetic superconductor remains open. Since Y9Co7 displays both SC and FM order at ambient conditions, this d-band metal offers a rare opportunity to study the condensation of Cooper pairs in the presence of a molecular field. We want to study this compound by ZF and LF-µSR technique.
DOI: 10.5286/isis.e.rb1610522
title: Muon spin rotation and relaxation studies of the multiband filled skutterudite superconductor LaRu4As12

description: The understanding of the pairing mechanism in unconventional superconductors in strongly correlated electron systems is a major theoretical challenge. In conventional s-wave superconductors, only the gauge symmetry is broken. If the pairing is not conventional, then some other symmetries of the Hamiltonian may be broken below Tc. We had given beam time on MuSR (RB1520431, 4 days) to investigate superconducting properties of LaRu4As12 (Tc=10.3K) and LaOs4As12 (Tc=3.2 K) ﬁlled-skutterudite compounds. However, we could finish measurements on LaOs4As12 only as we needed 5 different TF applied field runs between 0.1K and 4 K due to low Hc2. Here we request beam time on MuSR to completer the zero-ﬁeld (ZF), transverse field (TF) and longitudinal field (LF) µSR investigations on the multiband superconductor LaRu4As12 to study microscopic superconducting properties.
DOI: 10.5286/isis.e.rb1670530
title: Possibility of valence-tuning-induced magnetic order in S=1/2 Ru-dimer metallic complexes
DOI: 10.5286/isis.e.rb1670580
title: The first muSR measurement of magnetism in the T*214 cuprate

description: We propose the first muSR measurements on T*-structured La0.9+x/2Eu0.9+x/2Sr0.2-xCuO4 to investigate the effect of hole-doping and the oxygen annealing on the magnetism. Since the existence of strong AF correlation in the SC phase is suggested by ARPES, the magnetic correlation evolves in a different way from that in hole-doped T-La2-xSrxCuO4. Furthermore, the superconducting phase emerges after the oxygen annealing, which is opposite manner to the reduction annealing in the case of electron doped T'-Nd2-xCexCuO4.Therefore, T*-system provide a opportunity to extract a fundamental role of magnetism for the emergence of superconducting phase from a comparison with results for T-La2-xSrxCuO4 and T'-Nd2-xCexCuO4.We will draw AF ordered and SC phase diagrams for as-grown and oxygen annealed samples, and get information on the macroscopic coexistence of AF and SC phases.
DOI: 10.5286/isis.e.rb1700078
title: Single- and Multibit SER Measurements of semiconductors for recent technology nodes

description: Modern semiconductor-based components used, e.g., in automotive vehicles, contain registers and random access memory (SRAM). Due to naturally occurring ionising radiation, a.o. neutrons due to cosmic high-energy radiation interacting with the earth's atmosphere, these SRAMs and logic registers are prone to so-called 'bit-flips', e.g. changing the information content stored within the memory cells.To ensure the functionality of the electronic components and to be able to implement appropriate safety measures, the amount of bit-flips, the so-called 'soft-error rate' (SER) has to be determined in accelerated measurements.Measurements of the neutron SER using a beam which resembles the terrestrial neutron flux is currently only possible at two places, Los Alamos and ChipIR at RAL.We want to determine the single-bit and multi-bit upsets induced by neutrons on recent technology nodes.
DOI: 10.5286/isis.e.rb1710087
title: Cavitation processes in gas desorption experiments.

description: The aim of the experiment is to improve understanding of the onset of the cavitation process in desorption, in order to, ultimately, better understand adsorbate behaviour and thereby obtain more accurate pore structure characterisations with this method. It is proposed to monitor the changes in condensate structure, as the desorption knee is approached from higher pressures, in a variety of samples where cavitation might be anticipated to occur. The experiment will use model ordered silica materials with a variety of templated pore structures with the pore-body pore-neck type geometry expected to facilitate cavitation. The neutron data will be analysed using Empirical Potential Structure Refinement methods to extract information on the liquid structural density to detect signs of stretching of meta-stable adsorbed states.
DOI: 10.5286/isis.e.rb1710128
title: SANS investigation into structure and mechanism of low molecular weight organogelators (LMWOs)

description: The aim of this research is to study the self-assembly mechanism and arising structures for a range of low molecular weight organogelators (LMWOs). The structural characteristics of the gelators will be varied and the correlated molecular properties with gel properties through chemical modification, temperature, concentration and solvent variation will be examined using SANS. Preliminary SANS results (Figure 2a-b) indicate that the gelation temperature is concentration dependent, and the molecular self-assembly process is reversible as the temperature cycle of heating/cooling does not affect the aggregation structure.
DOI: 10.5286/isis.e.rb1710134
title: Direct spectroscopy of muon donor and acceptor levels in silicon carbide

description: We will perform direct laser spectroscopy to measure the ionisation energy of muon defect levels in a semiconductor - specifically silicon carbide. We should see a broad absorption band with a sharp cutoff at low energy. Time domain data, particularly in low transverse fields, will confirm which muon sites or charge states are involved. We will follow the ionisation edge and therefore defect depth as a function of temperature.
DOI: 10.5286/isis.e.rb1710216
title: Structures and thermal expansivity of recovered phases of urea II & III

description: Urea is a prototypical hydrogen-bonded small molecule that has stimulated considerable fundamental research into its structure, elastic properties and polymorphism. Amongst the high-pressure phases, the structure of urea II is unknown. Our DFT calculations on urea III reveal an uncommon elastic property, which is negative linear compressibility (i.e., one direction in the crystal expands when the crystal as a whole is compressed). This has recently been observed experimentally. We propose to use new STFC funded apparatus to form urea II and urea III and then recover them to room pressure under liquid nitrogen. This allows us to obtain the highest-resolution neutron powder diffraction data, which will enable structure solution of urea II and high-precision thermal expansion measurements of both polymorphs. We will correlate the thermal expansion with H-bonding and high-P compressibility.
DOI: 10.5286/isis.e.rb1720038
title: Design of new Ruddlesden Popper phases through sulphate/chromate incorporation

description: The drive for increasing energy efficiency and reducing greenhouse gas emissions has garnered increasing support for the use of fuel cell technology, which offers the potential for applications ranging from transport to stationary power generation. In terms of the latter, solid oxide fuel cells, which represent all solid state systems operating at elevated temperature (500-1000C), are the preferred option.  In this area, there is a drive to develop new materials with improved properties. In this experiment we aim to investigate the structures of a range of new sulfate/chromate doped Ruddlesden Popper systems of interest as new cathode materials for such applications. A key aim is to investigate any ordering of the chromate/sulfate groups and improve our understanding of their accommodation in these technologically important structures.
DOI: 10.5286/isis.e.rb1720098
title: Local magnetism, magnetic fluctuations and disorder, and lattice distortions in TbMn0.98Fe0.02O3 single crystal studied by muon SR

description: We aim at performing temperature (2-300K) and magnetic field (0-5T) dependent muon SR on a 1X1 cm2 mosaic, made of 4* 5x5x2 mm3 TbMn0.98Fe0.02O3 single crystals (largest area perpendicular to a-axis) in the HiFi beamline. The main objetives of this experiment are: 1) obtain a local perspective of the ongoing magnetic interactions and distortions due to the effect of Fe3+; 2) characterization of the spin dynamics and fluctuations, as well as, the distribution of local magnetic field, which depends on the commensurability or incommensurability of the spin structure. By joining the muon SR results with those already obtained from neutron diffraction, we expect to disentangle the complexity and origins of the local magnetic fields, disorder and fluctuations due to Fe3+ doping and applied magnetic field, and the disappearance of the electric polarization with increasing magnetic field.
DOI: 10.5286/isis.e.rb1720128
title: Alkali metal/ammonia intercalates of Bismuth Selenide

description: We have recently shown that the topical layered compound bismuth selenide which is of interest in the field of thermoelectrics and topological insulators can be intercalated by lithium and potassium ions which remain solvated by ammonia. We will use neutrons to characterise the structure of the intercalate compound synthesised from A/ND3 and A/NH3 (A = Li, K) solution and will use low temperature measurements to localise the intercalate species.
DOI: 10.5286/isis.e.rb1720183
title: Structures of ethanol  ammonia cocrystals

description: Compounds of ethanol and ammonia have been known for over a century but no structural characterisation has ever been carried out. These materials allow us to examine a range of different weak hydrogen bonding interactions and offer the intriguing possibility of a novel guest-host type of framework in which the host lattice is entirely comprised of ammonia. Since the liquids in this system are rather viscous, the most straightforward method of synthesis is to flash-freeze stoichiometric solutions in liquid nitrogen and then to examine the resulting polycrystalline samples using powder diffraction. This technique worked well for the methanol-ammonia co-crystals examined on HRPD in 2010 allowing this author to determine their complete structures very quickly and easily.