cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1510324
title: Determining the Induced Magnetism in Graphene by High-Angle Polarised Neutron Reflectivity

description: The aim of this proposal is to measure the induced magnetic moment in graphene arising from the proximity effect in the vicinity of a ferromagnetic substrate using high-angle Polarised Neutron Reflectivity (PNR) measurements at the POLREF endstation at ISIS, STFC. We thereby aim to identify and quantify the spin splitting in the graphene lattice by unambiguously determining the induced magnetic moment at 5 K.
DOI: 10.5286/isis.e.rb1510439
title: Full reciprocal space imaging of the acoustic phonons in MgV2O4:

description: The proposal requests time to obtain a full mapping of the low-energy acoustic phonons.  We have measured an acoustic phonon anomaly associated with the structural transition and request the use of MERLIN to obtain a full mapping of the acoustic phonons to determine the nature of the anomaly.  The proposals for 8 days of time to complete this proposal.
DOI: 10.5286/isis.e.rb1510509
title: Magnetic phase diagram in CeRh0.4Co0.6In5:

description: The '115' phase diagram shows a delicate interplay between strongly correlated magnetism and unconventional superconductivity with similar order parameters to high temperature cuprate and iron based superconductors.  We propose to initiate a study on a material in this phase diagram which shows the unusual feature of having both bulk antiferromagnetism and superconductivity.  This system is known to display two magnetic phase transitions and we wish to investigate these as a function of magnetic field and temperature to understand the phase diagram and the effect of superconductivity on this order.  The proposal requires the use of WISH and will be performed on a single crystal 200 mg plate to minimize effects due to absorption from In and Rh.
DOI: 10.5286/isis.e.rb1510610
title: Liquid Structure of Amino Acid Ionic Liquids Based on a Spectator Cation

description: Ionic liquids based on biocompatible ions such as amino acids are of significant interest since they offer access to a lower-cost and lower-toxicity family of green solvents for industrial processes. We have previously investigated a set of ionic liquids based on a standard cation paired with anions based on glycine, alanine, and serine, in order to understand the structural aspects of the liquid state, and highlight key interactions present in these systems.  We found interesting, strong correlations between anions in the system, with a stronger degree of association than would normally be seen.Here we aim to study ionic liquids using the same trio of amino acid anions, but paired with a weaker, less-associating cation in order to further push the structural association of anions in the system, and probe the reasons behind observed changes in trends of physicochemical properties.
DOI: 10.5286/isis.e.rb1520131
title: Measurement of average phase elastic strains and load sharing in complex multiphase Hot Isostatically Pressed stainless steel alloys

description: Rolls-Royce have developed a Co-free stainless steel hardfacing alloy for use in Pressurised Water Reactors called RR2450, produced using Hot Isostatic Pressing (HIP) as the manufacturing route. We have found that the RR2450 alloy develops a triplex austenite/ferrite/silicide matrix after HIPing. Precipitates in the form of Cr and Nb carbides are also present extensively. The silicide phase is a new phase in steel. Our research has shown that the presence of this phase is potentially an attractive aspect of this alloy since it has extremely high hardness. In order to better understand the deformation behaviour of this alloy and in particular, the evolution of phase specific elastic strains and the load sharing/transfer between the hard and soft phases in this alloy, we propose to carry out in situ compression tests at room temperature using the ENGIN-X neutron beamline.
DOI: 10.5286/isis.e.rb1520396
title: Oxidation of bilayer of DPPC  on a mineral interface by aqueous OH radical kinetics and mechanistic information for Atmospheric Science

description: Oxidation of atmospheric aerosol can produce cloud condensation nuclei capable of changing the reflectivity and lifetime of clouds. The oxidation of organic film on atmospheric mineral dust may activate mineral dust  into cloud droplets. To assess the atmospheric importance the chemical lifetime of the organic material to a common atmospheric oxidant (OH radical) must be measured and compared to deposition lifetime of the mineral aerosol (4-10 days). The chemical lifetime will be assessed by measuring the rate of oxidation of a bilayer of a lipid DPPC from the solid-liquid interface of a silica mineral window, using neutron reflection. Selective deuteration, the ability to measure film thickness and amount of material at the solid-liquid interface will allow chemical mechanism to be deduced. Preliminary studies show the experiment viable, and these data are needed for publication.
DOI: 10.5286/isis.e.rb1520400
title: Structure of zinc sulfide quantum dots from reverse Monte Carlo refinement

description: Zinc sulfide nanoparticles have a wide range of potential applications, in particular due to their optical properties. Research has enabled ZnS nanoparticles to be prepared with different coatings and different sizes. In this proposal we use neutron total scattering (including the small angle scattering) coupled with modelling via the Reverse Monte Carlo method to determine the atomic structure of a range of nanoparticles with different coatings and different sizes.
DOI: 10.5286/isis.e.rb1610102
title: Anhysteretic superelastic behaviour in Shape Memory alloys at transcritical temperatures

description: Shape Memory Alloys (SMAs) are a special kind of active materials in which the martensitic transformation (MT) is the basis of the peculiar superelastic, and shape memory effects of great interest for technical applications.In a recent work, by studying a tensile stress-induced MT in a Ni-Fe(Co)-Ga crystal we discovered a new phenomenon consisting in unusual anhysteretic superelastic behaviour associated with a very large strain equal to about 14% at above a critical temperature value.With a diffraction experiment covering the full sample volume under stress, we would definitively clarify the microscopic mechanism responsible for the unusual superelastic behavior.The experiment will show if the model is valid for describing this unusual behaviour and will give a sound basis for applying this theory to similar alloys with applications in solid state refrigeration.
DOI: 10.5286/isis.e.rb1610125
title: The lattice parameter displacements in kamacite and taenite phases in metallic meteorites. Are they generated by real strain?

description: The bulk of metal meteorites consists of the Fe,Ni-alloys kamacite [α-(Fe,Ni), bcc structure] and taenite [γ-(Ni,Fe), fcc structure]. The chemical composition is dominated by Fe and Ni, which make up more than 95%. Nickel is always present with a concentration ranging between 5 and 25%. Previous Time-of-Flight Neutron Diffraction experiments using the INES beamline were carried out aiming to characterize the quantitative amount of the two main phases and their microstructure. The results were useful for the characterization of the samples but also evidenced some anomalous and very interesting trends in lattice paramter values. A possible explanation of this phenomenon requires the presence either of residual stress or of micro-structural phenomena. If confirmed, the presence of residual stresses in iron meteorites would tremendously affect the research on planetary science.
DOI: 10.5286/isis.e.rb1610411
title: Probing competing quantum effects in the protic ionic liquid ethylammonium nitrate

description: Protic ionic liquids are salt formed by a Bronsted acid and a Bronsted base. Proton transfer occurs from the acid to the base, creating a complex network of hydrogen-bonded (HB) ions. However, given the complex molecular structure of cations, it is possible to identify protons participating to the HB network depending on the belonging to a given molecular subgroup. This property makes them suitable model systems to characterize competing intramolecular and intermolecular quantum effects. By exploiting selective isotope substitution, it is our aim to characterize nuclear quantum effects in both HB and non-HB protons, as well as their interplay, in the prototype protic ionic liquid ethylammonium nitrate.
DOI: 10.5286/isis.e.rb1610458
title: The Effect of Low Transformation Temperature Welding Alloys on the  Residual Stress Distribution of Full-Penetration Multi-pass Butt Welds

description: The aim of this experiment is to characterise the effect of a low-transformation temperature (LTT) welding alloy on the residual stresses of multi-pass, full-penetration welds. The specially designed welding electrode exploits transformation plasticity to offset thermal contraction strains generated during welding. Three welds, produced with different filler alloys, will be assessed for comparison. Due to the multi-layer and full-penetration nature of the welds, the residual stress distributions are expected to be asymmetric, hence reflecting, for the first time, those in 'real' welded joints. The residual stress distributions measured by neutron diffraction will be correlated to the welds' fatigue performances under various loading conditions. The proposed experiment is an essential part of a PhD project jointly supported by the University of Cambridge and TWI Ltd.
DOI: 10.5286/isis.e.rb1620169
title: Orientational and conformational disorder in a halogen-ethane compound

description: The translational and orientational disorder of some liquids can be frozen if they are cooled down quick enough, giving rise to a Structural Glass (SG). But for some molecular compounds molecules displaying pseudo-globular shape can rotate around the equilibrium positions of a crystalline lattice, the quenching can lead to the so called Orientational Glass (OG), in which the orientational disorder is frozen while the long-range translational order still persists. That is the case of some simple halogen-ethane compounds. In addition, the existence of conformational disorder (trans and gauche conformers) which can hybridize with sound modes in both the OG and the ordered low-temperature phases makes relevant the study of the anomalous enhanced vibrational density of states in the low-frequency spectral range over the predicted one by Debye for the low-temperature ordered solid phase.
DOI: 10.5286/isis.e.rb1620193
title: Neutron Diffraction Studies on Li-rich or Ni-rich Layered Oxides Cathode Materials of Lithium Ion Battery

description: Lithium-rich or Ni-rich layered oxides cathode materials have attracted great attentions owing to their high specific capacity for lithium-ion batteries. But the poor rate capability and voltage fade of lithium-rich layered oxides cathode materials have limited their practical applications. The degree of Li/Ni mixing not only affects the rate capability but also the structure stability and the cycling stability. In this experiment we propose to examine in detail the crystal structures of Ni-rich LiMn0.8Ni0.1Co0.1O2 and Li-rich Li1.2Mn0.6Ni0.2O2, in order to determine the degree of Li/Ni mixing of the materials, determine the occupations of the different sites by transition metal elements (Fe, Ni, Co, Mn, Zr) of similar mass weight, and give new insights about the structure-performance relationship and instruct the structure design and optimization for high performance electrode materials
DOI: 10.5286/isis.e.rb1620321
title: Powder Averaged magnetic fluctuations in Cu3Nb2O8

description: Cu3Nb2O8 is an unusual multiferroic compound in that the electrical polarisation is oriented perpendicular to the common plane of rotation of the spins.  We propose to begin a study of the magnetic interactions in this material by first measuring the powder averaged spectra.  This will provide the energy scales to guide future efforts on single crystal measurements.  The proposal requests 3 days on the MARI spectrometer.
DOI: 10.5286/isis.e.rb1620465
title: Alloxan - a high density organic under pressure

description: Organic molecular crystal structures have densities that are typically in the range 1.2-1.4 gcm-3 although these can be increased, in general, to ca. 2.0 GPa through application of pressure. However, the organic heterocycle alloxan is an anomaly, measuring 1.962 gcm-3 at ambient conditions. Compression of an already-dense material gives us a head-start, enabling us to explore a high-density region of phase space that would otherwise require improvements in pressure equipment for typical organics. We will observe the compression mechanism of alloxan, up to 10 GPa, and quantify the strengths of its intermolecular interactions, as it experiences abnormally high densities, in the context of organic structures. Alloxan also undergoes a transition from P41212 to P212121 at 35 K and we will aim to see whether this transition can also be induced via pressure.
DOI: 10.5286/isis.e.rb1620474
title: A comparative NR study of interaction of short designed antimicrobial peptides to accurate gram negative and red blood cells model membranes

description: The global increase of bacterial resistance to antibiotics has led to increasing interest in research focusing on the development and characterization of new antimicrobial agents. One class of promising antimicrobials found in nature are Antimicrobial Peptides (AMPs) [1]. In contrast to most existing therapeutic antimicrobials, and so it is thought that resistance would be far more difficult to develop to AMPs. We have designed a novel class of AMP's with the general sequence G(IIKK)nI-NH2, with n-the number of coils of α-helix (n=2-4). In a recent experiment we have studies the interaction of these peptides with floating bilayers intended to mimic gram negtive of eukaryotic membranes, and obesrved changes to membrane structure on binding. In this experiment we wish to extend this preliminary work by studying the concentration dependence of peptide interaction with membranes.
DOI: 10.5286/isis.e.rb1620476
title: Geometrical frustration induced quantum phase transition in CeRh1-xPdxSn: Inelastic neutron scattering study

description: The quasi-kagome Kondo lattice CeRhSn exhibits intriguing properties, which ascribe to 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 recently study of CeRh1-xPdxSn series reveals magnetic transitions for x ≥ 0.4 and on MERLIN express we show well defined  CEF excitations in x=0.8. 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. For the study of quantum phase transition, the system CeRh1-xPdxSn warrants to be further studied by inelastic neutron scattering experiment.
DOI: 10.5286/isis.e.rb1700064
title: Power devices failure rate evaluation under neutron irradiation in ChipIr

description: The power electronic devices are subjected to terrestrial radiation field and they result particularly sensitive to the terrestrial neutron field. Neutrons interact with the power devices and cause significant damages. Single Event Burnout (SEB) is the most relevant damage caused by neutrons interaction with power electronic devices and it causes their completely destruction. We performed preliminary tests on power devices, and in particular on Power MOSFETs, in two different neutron facilities: ANITA Neutron Facility of the Uppsala University (Sweden), and 241Am-Be Neutron Irradiator of the University of Palermo (Italy). These preliminary tests underlined the Power MOSFETs sensibility to the neutron irradiation and demonstrated the neutron capability to induce SEB.
DOI: 10.5286/isis.e.rb1710067
title: Adsorption of surfactants used in fire-fighting foams

description: The aim is to use Neutron Reflectivity (NR) to gain essential information on adsorption properties of practical fluorotelomer surfactants used in fire-fighting foam formulations (Figure 1). NR is needed to further understanding how molecular packing in air-water interfacial films influences surface tensions. These surfactants have already been studied individually by SANS and this provided necessary information on the self-assembled structures in solution. This is the first stage in a new 3-year program, including NR, so that F-carbon surfactants can be replaced by more environmentally-responsive low-F or hydrocarbon analogues. A sister proposal has been submitted this round to study aggregation of these surfactants as mixed systems by SANS (Micellization in mixtures of surfactants used in fire-fighting foams).  Chris Hill is a 2nd year PhD student fully funded by Angus Fire.
DOI: 10.5286/isis.e.rb1710129
title: The crystal structure and magnetic properties of Sr2PrCr2BO9 (B=Sb, Nb, Ta)

description: In previous work we described La3Ni2SbO9 as the first example of a relaxor ferromagnet.  We aim to understand what is special about La3Ni2SbO9 and synthesise new (A,A)3M2BO9 compounds that show relaxor ferromagnetism at higher temperatures. We have synthesised three new compounds, Sr2PrCr2SbO9, Sr2PrCr2NbO9 and Sr2PrCr2TaO9, so we can investigate what effect a different magnetic cation has on the magnetic properties. All three compounds show two magnetic transitions at 150 K and 20 K. We wish to collect data on GEM at 5K, 60 K and 300 K so that we can determine the crystal and magnetic structures above and below each magnetic transition. We will then compare these structures with those of nickel and iron analogues to help us understand what factors are important in creating a relaxor ferromagnet.
DOI: 10.5286/isis.e.rb1710191
title: Observation of hydrogen diffusion in hydrogen storage materials with muSR

description: This is a continuation proposal describing an "in situ" muSR experiment on hydrogen storage materials. For the two previous beam-time allocated for RB1510262 and RB1520259, we have made a special cell for measuring the muSR spectrum and the amount of gas desorbed from the sample simultaneously. Using such cell, we have found that hydrogen starts to diffuse in the milled MgH2 sample below its hydrogen desorption temperature (RB1610029). This indicates the importance of H diffusion in solids to determine the desorption temperature in MgH2. In order to check whether such relationship is a common phenomenon in complex hydrogen storage materials, we wish to perform the "in situ" muSR experiment on borohydrides. Note that we already measured the muSR spectra for LiBH4 and other samples at temperatures far below their desorption temperature (RB1520259).
DOI: 10.5286/isis.e.rb1710315
title: Detecting quantum critical fluctuations in the distorted kagome Kondo compound CeRhSn

description: Geometrically frustrated spin systems have been studied extensively for decades because of many intriguing phenomena, exemplified by the non-magnetic quantum disordered states.  On the other hand, there is a long history of studying interactions between the localized and conduction electrons in Ce or Yb compounds, which typically results in the Kondo-lattice or valence-fluctuation states.  A combination of such Kondo-lattice state and geometrical frustration becomes a new topic, both enhancing quantum fluctuations in different routes.  In this proposal, we would like to investigate CeRhSn, which  is recently found to be a model compound belonging to this new class.   We would like to elucidate the origin of quantum critical behavior detected in the bulk measurements by investigating its low-energy spin fluctuations in detail.
DOI: 10.5286/isis.e.rb1710382
title: An exploration of the vibrational properties of energetic materials using Inelastic Neutron Spectroscopy

description: We have initiated a new research programme that seeks to correlate features of the crystal structures of energetic materials (explosives, propellants) with their sensitivities to initiation by impact and shock.  The ultimate aim is to develop a methodology for predicting the sensitivities of energetic materials based on their crystal structures. The development and validation of such a model would be of immense value to industrial and academic efforts to produce safer materials, and the approach has the potential to revolutionise the targeted design of materials.  The firts aim is to investigate experimentally the vibrational properties of selected energetic materials for the validation and enhancement of theoretical models of impact and shock sensitivity using inelastic neutron scattering. The second aim is to validate the calculations of vibrational properties in molecular materials.
DOI: 10.5286/isis.e.rb1710456
title: Structure and dynamics of nano-confined supercooled water studied by Deep Inelastic Neutron Scattering

description: Studies on the structure and dynamics of nano-confined water are relevant and up-to-date not only for the understanding of the physics of water bu also for their implications in biophysics, biopreservation and pharmaceutics. In this proposal we plan to measure, via DINS experiments at VESUVIO, the temperature profile (in the range 180-290K) of the mean kinetic energy of hydrogen and oxygen atoms of supercooled water confined within the pores of a disordered hydrophilic silica matrix (silica xerogel - a good model system for water confined in biophysical systems). Our aim is to obtain experimental evidence of the so-called Low Density Liquid - High Density Liquid crossover that is deemed to occur at 225 K in confined water and has been suggested to be linked to the activation of functionally relevant anharmonic motions in proteins.
DOI: 10.5286/isis.e.rb1510100
title: Study of superconductivity in CaPd2As2, SrPd2As2 and CaPd2Ge2 using muon spin relaxation and rotation

description: The discovery of superconductivity in ThCr2Si2 type tetragonal Fe-based compounds (i.e. YFe2Ge2) have generated considerable interest. Recently we found bulk superconductivity in CaPd2As2, SrPd2As2 and CaPd2Ge2 with transition temperature Tc = 1.3 K, 0.9 K and 1.7 K, respectively.  Investigations of superconducting properties by electrical resistivity and heat capacity measurements reveal electron-phonon mediated weak coupling type-II superconductivity possibly with a moderately anisotropic s-wave gap. It would be of interest to further investigate the superconducting properties of CaPd2As2, SrPd2As2 and CaPd2Ge2 using muon spin relaxation and rotation (µSR) technique to find out whether the time reversal symmetry is broken or not. We therefore propose to carry out µSR study on these compounds using the MUSR spectrometer.
DOI: 10.5286/isis.e.rb1510219
title: Muon Spin Relaxation study on heavy fermion oxypnictide Ce(Ru1-xFex)PO

description: Recently the ferromagnetic quantum criticality (FQCP) has generated considerable interest both in theoretical and experimental condensed mater physics. The heavy fermion oxypnictide Ce(Ru1-xFex)PO is an ideal system to investigate the ferromagnetic quantum criticality. The heavy fermion CeRuPO exhibits ferromagnetic ordering at Tc = 15 K whereas the heavy fermion CeFePO remains paramagnetic down to 80 mK. Partial substitution of Ru by Fe suppresses the Tc and a FQCP is realized near x ~ 0.86. Further, indications of local quantum criticality of f-electrons are found. In order to further explore the FQCP and scaling behaviour in Ce(Ru1-xFex)PO it will be of interest to investigate the magnetic properties of these compounds using muon spin relaxation technique as the muons are sensitive  to extremely small magnetic field. We therefore propose to carry out µSR study on Ce(Ru1-xFex)PO.