cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1510393
title: The structure of the Bam complex, the Gram-negative outer membrane protein folding machinery

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. Key to this understanding is the knowledge of the structure of the complex and its individual components. We aim to continue our investigation of the Bam complex by studying the BamAB, BamCDE and complete BamABCDE complexes and in particular identify how the individual components are organised with respect to each other. To do this will use Small Angle Neutron Scattering and specific deuteration, in concert with a previously collected SANS dataset of the BamCDE sub complex, to probe the structure of the full Bam complex for first time.
DOI: 10.5286/isis.e.rb1510531
title: Elucidating Lattice Dynamics of Metal-Organic Frameworks via Inelastic Neutron Spectroscopy

description: The proposed work will employ Inelastic Neutron Scattering (INS) spectroscopy at TOSCA to establish vibrational frequencies in porous metal-organic frameworks (MOFs). MOFs adopting zeolitic topologies (ZIFs and TIFs) will be studied. The aim is to establish detailed low-energy vibrational modes of MOFs, featuring distinct chemical structures, network topologies and pore configurations.
DOI: 10.5286/isis.e.rb1510615
title: Conformations in partially mixed block copolymers of partially deuterated polyethylene.

description: Nascent 'disentangled' block copolymers of Ultra-high Molecular Weight Polyethylene (UHMWPE) with a reduced number of entanglements were synthesized having protonated (hPE) and deuterated (dPE) PE blocks. Due to different melting temperatures of the block materials in our copolymers we expect to be able to separately change the entanglement density and crystallisation state (nascent or melt-crystallised) of each block. Both of these characteristics provide distinct scattering shapes allowing us to follow these changes, so that we will be able to see how the dPE and hPE blocks mix and entangle with each other as well as within their own regions. This gives new insight related to the question of how well long chains of deuterated and protonated polyolefins mix and, crucially, how this mixing is influenced by the density of entanglements and original crystalline structure of the polymer.
DOI: 10.5286/isis.e.rb1520299
title: Remanence driven assembly of magnetic nanoparticles on a silicon wafer coated with amorphous film having strong perpendicular anisotropy

description: Ferrofluids are liquids having magnetic nanoparticles dispersed in a solvent and covered with surfactants to prevent them from agglomeration. The particles can form smectic like ordering in the presence of magnetic field. We are interested in the interaction of magnetic particles with a magnetized solid wall (TbCo). Particles are held as magnetic dipoles aided by the perpendicular anisotropy of amorphous TbCo layer and are attracted by its gradient field. Thus, mono- to multilayers are likely to form by self-assembly even in remanence magnetization state of TbCo layer. Our interest is to study this self-assembly process with respect to different parameters, like ferrofluid concentration, film thickness. The self-assembly process can be rather slow. Neutron reflectivity and grazing incidence scattering will allow us to study the kinetics of the self-assembly and the equilibrium structure.
DOI: 10.5286/isis.e.rb1610118
title: Suppression of quantum fluctuations by high magnetic field in one- and two-dimensional spin-1/2 magnets.

description: Fluctuations in the properties of materials at low temperatures give rise to unusual and exotic effects. These fluctuations, quantum mechanical in origin and allowed by the Heisenberg uncertainty principle, affect both magnetic and metallic systems, and could be responsible for formation of high temperature superconductivity in certain materials. These effects are expected to be suppressed by applying high magnetic fields, but only limited experimental evidence for the suppression has so far been observed real materials. We propose measurements on two recently discovered magnetic materials which, owing to their molecular building blocks, allow access to a more extensive range of field-induced physics than was previously possible. We will make use of the 14 T superconducting magnet available at WISH, the instrument most ideally suited to this measurement.
DOI: 10.5286/isis.e.rb1610184
title: PROTON DYNAMICS IN NON AND PARTIALLY DEUTERIATED ETHYLAMMONIUM NITRATE IONIC LIQUIDS

description: The field of ionic liquids is one of the hottest topics with the number of publications still growing exponentially. This is due to the negligible vapour pressure, non-flammability, wide liquid, solubility and miscibility range of most ionic liquids. Ionic liquids have been often described as designer solvents, as properties of their ions can be changed to improve the suitability for a given process.  Protonated ionic liquids are excellent proton carriers in fuel cell electrolytes, providing electrolytes of a type that are simply not available in systems in which water acts as acid or base in the proton transfer process. But, there is a lacuna in our knowledge of these compounds.  Utilisation of beam time at ISIS will help us to shed light on proton behaviour processes of protonated ionic liquids.
DOI: 10.5286/isis.e.rb1610186
title: Time reversal symmetry breaking superconductivity in partially filled skutterudite PrxPt4Ge12

description: The unconventional filled skutterudite superconductor, PrPt4Ge12 (Tc~7.9K), was recently discovered, for wihch zero field muon spin relaxation (ZF-MuSR) experiments reveal that time reversal symmetry (TRS) breaking occurs below Tc. ZF-MuSR experiments in the (Pr,La)Pt4Ge12 alloy series reveal that Pr-Pr intersite interactions are important for the booken TRS. Superconductivity was also discovered in partially filled skutterudite Pr0.5Pt4Ge12 (Tc ~ 7.66K), however specific heat measurements suggest that this is a conventional superconductor. We Propose to use ZF-MuSR to investigate how the TRS-breaking superconductivity of PrPt4Ge12 evolves with the Pr filled percentage.
DOI: 10.5286/isis.e.rb1610363
title: Interface magnetism study of Fe/GaSb epitaxial structures

description: We propose to study the magnetic moment and the magnetic layer profile in order to rule out the presence of magnetic dead layers at the interface in thin Fe films grown epitaxially on GaSb/AlSb/GaAs(001) and GaSb(001) substrates as a function of thickness using polarised neutron reflectometry (PNR). Our goal is to obtain information of the magnetic depth profile of Fe and the magnetic interface between Fe and high spin-orbit coupling (SOC) material GaSb. This information will help us to better understand the magnetic-transport measurement results and the magnetic properties obtained by conventional magnetometry on our structures.
DOI: 10.5286/isis.e.rb1610424
title: Determining the Induced Magnetism in Graphene by Polarised Neutron Reflectivity

description: This proposal aims to unambiguously understand the proximity effect between graphene and a transition metal using Polarised Neutron Reflectivity (PNR) measurements at the POLREF instrument. Also to clarify whether the induced magnetic moment in graphene is due to the exchange interaction or because of shared electrons at the interface.
DOI: 10.5286/isis.e.rb1610510
title: Proving ground-state ordering in Artificial Spin-Ice systems formed by sub-100 nm nanomangets by means of PNR

description: The main purpose of the experiment proposed here is to study the effects of thermalisation on Artificial Spin-Ice (ASI) systems formed by nanomagnets with sub-100 nm lateral dimensions, by means of Polarized Neutron Reflectivity (PNR) analysis on different Bragg peaks. With this experiment we will be able to prove the existence of ground-state ordering in sub-100 nm ASI systems, as well as to quantitatively determine the disorder (deviation from ground-state) for any magnetization configuration present in the ASI pattern. These measurements will be the first-ever proof of the existence of ground-state ordering in sub-100 nm ASI systems, as current imaging techniques used so far to image ASI systems are beyond the resolution limit for such small nanomangets.
DOI: 10.5286/isis.e.rb1620260
title: Sample dynamics by quasielastic neutron scattering on the sub nanosecond scale using TOFLAR (Time Of Flight and LARmor precession) technique

description: TOFLAR is a new technique to study atomic motions on the time scale from a fraction of a picosecond up to one nanosecond. In contrast to some established techniques that only use time-of-flight to measure neutron energy, TOFLAR also uses precession of the neutron spin in a magnetic field. As a consequence, neither the incoming neutron beam nor the beam scattered by atomic nuclei present in the sample have to be monochromatized (by only keeping neutrons that have a particular energy, and discarding all other), and, therefore, neutrons are more efficiently used. In the proposed experiment we plan to test the feasibility and efficiency of TOFLAR by measuring dynamics of water molecules in liquid water as well as in gypsum powder.
DOI: 10.5286/isis.e.rb1620342
title: Neutron reflectivity study of the effect of thermal annealing on the morphology of bulk heterojunction PffBT4T-2OD:fullerene thin films

description: This projects aims to contribute to a better understanding of the relationship between processing conditions, active layer morphology and device performance in polymer solar cells (PSCs). To this end a series of Neutron Reflectivity experiments are envisaged, to provide the most detailed understanding possible of the processing-morphology-performance relationships in polymer:fullerene solar cells based on a polymer with the best power conversion efficiencies (PCEs), namely PffBT4T-2OD (also known as PCE11). Optimized organic photovoltaic (OPV) processing, with its associated low production costs, would radically change the renewable energy paradigm that is key for opening solar energy to new markets such as those in developing countries where people would not normally think about investing in and generating their own electricity.
DOI: 10.5286/isis.e.rb1620344
title: Multiscale time resolving study of the crystallisation of nanofibrils of a molecular gelator

description: This experiment exploits the unique capability of Nimrod to study the crystallisation of nanofibrils of a  molecular gelator dibenzylidene sorbitol from alkane solutions on multiple  length scales. Such gelators are used industrially to control polymer morphology. We wish to obtain high quality time-resolved neutron scattering starting from the quiescent homogenous solution and extending through the formation of crystalline nanofibrils. We wish to understand the crystal structure and morphology of these nanofibrils.  Our ultimate focus is on industrial crystalline polymers where the properties of products are strongly connected with the crystalline morphology  developed in the processing stage. By understanding the nanofibrils we can further develop our model of their behaviour in  polymers so we can help develop enhanced healthcare and industrial products.
DOI: 10.5286/isis.e.rb1620458
title: Photocarrier lifetime and its temperature dependence in doped silicon

description: In the previous beamtime, RB1520457, we have found that the relaxation rate can be used as a measure of the photocarrier density in intrinsic silicon. This method has been applied to measure the lifetime of photocarriers in two different temperatures. In this proposal we continue to measure the lifetime and its temperature dependence in doped silicon samples, which are important in many semiconductor applications. We also expect to observe an interaction between Mu and photoexcited minority carriers in doped silicon.
DOI: 10.5286/isis.e.rb1670574
title: Determination of muon stopping sites and electronic structures in proteins

description: In order to explore the electron-transfer process in life science, we have been carrying out muSR studies based upon electron labeling mechanisms on a protein, cytochrome c, which is a member of the respiratory chain. In order to deepen the understanding of these muSR data, we intend to determine the muon stopping sites and electronic structure. Our LF muSR data showed a level crossing resonance (LCR) signature for cytochrome c indicated that some portion of muon has a strong energy transfer at specific LF to the surrounding species at the stopping site. The observed LCR data was similar to that of polyglycine (F.Pratt, private communication) and would be attributed to quadruple LCR.  In this proposal, we examine LCR of N-methylacetamide, the simplest molecule containing a peptide bond,and glycine14N (Q=0.16) and15N (Q = 0)to confirm the stopping sites and possibility of QLCR.
DOI: 10.5286/isis.e.rb1710505
title: The effect of H/D isotopic replacement on the topology of the electron density in urea.

description: The Quantum Theory of Atoms in Molecules (QTAIM) is the quantum mechanical way of looking at molecular structures and bonding. Developed by Richard Bader, QTAIM is built on concepts proper to the molecular structure hypothesis in which a functional grouping of atoms has an additive and characteristic set of properties, and uses the topology of the electron density to investigate the interactions in molecular systems. We propose to use QTAIM as a detecting tool in order to identify small changes in the electron density due to weak forces. In particular we would like to test the power of topological analysis in revealing small effects of H/D isotopic replacement. Single crystal neutron diffraction data are vital for the correct description of atoms in the analysis.
DOI: 10.5286/isis.e.rb1720048
title: QENS studies of the interaction of propene with ZSM-5

description: Fluidised Catalytic Cracking (FCC) units are one of the major conversion units in modern petrochemical refineries. ZSM-5 additives are used in FCC units to convert gasoline (mainly gasoline olefins) into lighter C3 and C4 olefins (propene and butenes).  Propene is a key feedstock for downstream petrochemical industry and plays a major role in a variety of polypropene products in the market.  There is a global supply shortage of propene and improving propene yields from FCC units is seen as one strategy for meeting that supply gap. This proposal, and a parallel INS proposal, aims to understand how ZSM-5 reacts with propene.
DOI: 10.5286/isis.e.rb1720282
title: Verification of Local Ordering in Praseodymium Doped Ceria

description: Doped cerias are currently being used as oxide ion conducting electrolyte materials in solid oxide fuel cells (SOFCs). Depending on the nature and concentration of the dopant and the oxygen partial pressure (pO2), these materials can also act as mixed ionic-electronic conductors (MIECs). MIECs have a particular advantage for use in SOFCs as they allow for redox reaction over the whole surface of the electrode. This potentially allows for greater efficiency in these devices. We have recently performed a study of local structure in praseodymium doped ceria as a function of pO2 on the Polaris diffractometer. The results appear to show strong evidence of local order not evident in conventional Rietveld analysis. A short experiment is proposed to verify these results and eliminate possible sources of error to enable a publication to proceed.
DOI: 10.5286/isis.e.rb1720312
title: Investigation on the structural properties of doxorubicin-loaded PEGylated liposomes (Doxil®)

description: Doxil® is a marketed liposomal formulation containing the anticancer drug doxorubicin. Recently, SAXS measurements have evidenced a crystalline fibrillar structure for the encapsulated doxorubicin at 25°C. We have already performed a characterization of the thermal behaviour of the formulation by microcalorimetry, and high-resolution ultrasonic spectroscopy in order to investigate better the phase transition of the liposomal membrane and of the encapsulated drug. We propose here to perform SANS measurements on Doxil® and unloaded liposomes for comparison at four selected temperatures. As previously verified by preliminary spectra at 20°C, this technique, thanks to H2O/D2O sub-phase matching, is able to discriminate between the contribution of the phospholipidic components and drug nanocrystals. Thus, it represents a valid tool for the characterization of the thermal behaviour of Doxil®.
DOI: 10.5286/isis.e.rb1720331
title: Neutron scattering study of stress-strain behaviour of porous geological materials

description: Quantifying the relationship between stress-strain and fracture is important to the perfection of fracture capability if it is to be used as a tool for guiding failure operations in geological materials drilling. The development of fracture prediction tools is critical for geological applications in oil and gas industry as the prospects for building understanding empirically will be limited due to the high costs associated with extreme condition field trials (e.g. North Sea). There are numerous data associated with porous geological material fracture investigations, but the value of this information is limited by an inability to accurately measure stress-strain within the sample. This work aims to use neutron techniques that can be interrogate the internal volume of porous crystalline geological specimens subjected to stress states at high temperature resembling geological conditions.
DOI: 10.5286/isis.e.rb1720374
title: Muon Spin Relaxation Investigation of Mixed Cation Perovskite Solar Cell Materials

description: Perovskite solar cells (PSCs) are a new generation of solar technology which has shown huge promise with regards to performance, but still suffers from several flaws preventing it from making the leap from the lab scale to the commercial scale.  Many PSC show strong hysteresis in the jV curves  this means that a (much) higher efficiency is measured when scanning from open circuit to short circuit. The prevalent theory for explaining this hysteresis is that mobile ions in the material are responsible for it. Slight alterations to the chemical composition of the perovskite can help suppress hysteresis. The objective of this experiment is  to investigate how the diffusion of iodide is affected by systematic altering of the perovskite structure.
DOI: 10.5286/isis.e.rb1720496
title: MUSR study on the 112-type iron pnictide superconductor Ca1-xLaxFe1-yNiyAs2

description: One typical feature for the unconventional superconductivity is the neutron spin resonance in the doped antifer-romagnet, with a centering energy below or above the superconducting gap, which depends on the pairing symmetry and Fermi topology. In the new (Ca,La)FeAs2 system, the spin resonance energy is slightly larger as expected, and the Fermi surface nesting condition is poor, which may challenge the sign-reversed s-wave picture but cannot rule out the d-wave paring symmetry. Thus we propose to carry out zero-field (ZF),  longitudinal-field (LF) and ), transverse-field (TF) muon spin rotation and relaxation (µSR) measurements on Ca0.82La0.18Fe0.96Ni0.04As2 compound down to 0.3 K at the MuSR spectrometer, to determine the time reversal symmetry (TRS) below Tc,  superfluid density and pairing symmetry based on our high quality single crystals.
DOI: 10.5286/isis.e.rb1410248
title: Pressure & Temperature Phase Diagram of the Elpasolite Perovskite La2NiMnO6

description: This experiment will examine the pressure and temeprature phase diagram of the elpasolite perovskite La2NiMnO6. The sample will be studied in the pressure range of 0-9 GPa at termpatres from 120-1200 K. It will examine the P-T regions of stability of the two knbwon phases of La2NiMnO6 and also look for new pahses in the high pressure temperature regime. If new phases are discovered it is hoped to either recover them metastably or mimick the phases observed by chemicl tuning. In a test experiment the phase diagram has roughl;y been mapped out in the 0-4 GPa region from 120-400 K. Where a monoclinic to rhombohedral phase transition is observed it is hoped to map this transition more accuralty and look for possible higher symmetry phases at high pressur and temperature.
DOI: 10.5286/isis.e.rb1510015
title: New surfactants forming anisotropic micelles and microemulsions in CO2

description: An analogue of the popular surfactant AOT with isopropyl glycol tails (IG-AOT, Figure.1) has been recently designed as a co-surfactant for water-in-CO2 (w/c) systems: stable microemulsions are formed by mixing IG-AOT with a fluorinated surfactant nFG(EO)2 up to a significant water/surfactant molar ratio w=30. In a preliminary ISIS SANS experiment confirmed formation of elongated micelles at different pressures (Figure 2). Hence, since there are only few reports of similar systems in the literature , this new IG-AOT system deserves further study. Here, experiments are proposed to investigate the structure of IGAOTw/c microemulsions under a range of conditions, and therefore, the ability to act as a liquid CO2 viscosity modifier can be evaluated.
DOI: 10.5286/isis.e.rb1510036
title: ADVANCED POLYMER MATERIALS FOR ENERGY SECURITY (POLYMAT)

description: This proposal requests time on NIMROD at ISIS to enable the characterisation of polymer nanocomposite interfaces. This information will be used as part of a wider effort for which EPSRC funding is being sought. However the ISIS proposal also stands in its own right and can be achieved with or without EPSRC funding. Our hypothesis is that the insulating properties of nanocomposite materials are controlled by the  nanoparticle/polymer interface. Once the interfaces are characterised the electrical properties of the nanocomposites can be related back to the interfacial properties through calculations of the density of excess electron states and corresponding mobilities.  We propose to combine neutron and x ray scattering data, which will be crucial for the determination of the contribution of surface trapping states to insulator performance.
DOI: 10.5286/isis.e.rb1510041
title: Inelastic Neutron Scattering Studies of Gas-Loaded Porous Framework Materials

description: This proposed study will investigate the interactions exhibited by some weakly scattering gas substrates (NOx and small hydrocarbons) at different loadings. We request 13 days on TOSCA to study the interaction of adsorbed gas molecules (NO2, NO, N2O, C2H2, C2H4, C2H6, C3H6 and C3H8) within two new porous MOF materials [NOTT-300(V) and NOTT-300(V,Al)]. These MOFs exhibit extremely high selectivity for unsaturated hydrocarbons and NOx at ambient conditions, with high uptake capacities, suggesting the presence of specific guest/host interaction. The proposed study aims to reveal the nature of these selective gas uptake properties by analysing the guest/host interaction.
DOI: 10.5286/isis.e.rb1510130
title: The Effect of Pressure on the Low Temperature Magnetic Structure of the CMR Material NdMnAsO0.95F0.05

description: Colossal magnetoresistance (CMR) is observed in the oxypnictide NdMnAsO1-xFx (x = 0 - 0.085) at low temperature. The CMR in NdMnAsO1-xFx arises due to competition between a strongly correlated antiferromagnetic insulating phase and a paramagnetic semiconductor with field. Another way to induce transitions between competing phases is to apply external pressure. Preliminary variable pressure data show a notable change in the temperature variation of the resistivity of NdMnAsO0.95F0.05 upon applying a pressure of up to 2.56 GPa. Given that the electronic and magnetic properties of NdMnAsO0.95F0.05 are strongly coupled it is highly likely that this change in resistivity is a result of a change in magnetic structure upon applying pressure. We aim to investigate the magnetic structure of NdMnAsO0.95F0.05 at temperatures between 20 K and 60 K in pressures up to 6 GPa.