cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1720087
title: Solving the mystery of destabilized complex hydride Ca(BH4)2-Mg2NiH4: the chemistry of boron

description: The composite system Ca(BH4)2-Mg2NiH4 is the first reported that has an effective boron transfer between the compounds of the mixture, which makes it ideally suited for a reversible hydrogen storage system.Using the Kalpha/Kbeta ratio from muonic X-rays emitted by boron, which is sensitive to the local environment, we would like to identify which phases are present in the system upon desorption of hydrogen and when H2-absorption triggers the return of boron in the native Ca(BH4)2 framework.To obtain this achievement, we will use high-resolution measurements of X-ray emission from boron and such results are expected to have a pioneering nature in making Muonic X-ray technique a local probe comparable to X-ray emission spectroscopy.
DOI: 10.5286/isis.e.rb1720388
title: Thermal expansion of recovered high-pressure ice polymorphs

description: The ambient-pressure phase of ice is a well-known example of a molecular solid that exhibits negative volume thermal expansion below 60 K. In a recent study carried out on HRPD we determined that ice III displays negative area expansion below 45 K, and also obtained some evidence that ice V has negative linear  expansion at low temperature. Due to the fundamental interest in this type of anomalous thermo-elastic property and both the ubiquity and variety of ice polymorphs, a thorough characterisation of the thermal expansion of other high-pressure ice phases is warranted. This proposal seeks to determine the thermal expansion to high precision of ices II, V and VI in the range 10 - 150 K, along with complementary structural information. These will be prepared offline in a piston-cylinder cell and then recovered under liquid nitrogen for analysis on HRPD.
DOI: 10.5286/isis.e.rb1820434
title: Probing Charge, Orbital and Magnetic Ordering in the Solid Solution of the Multiferroic Ca1-xNaxMn3Mn4O12 and Ca1-xLaxMn3Mn4O12

description: Multiferroics  materials where an electric polarisation may be switch by the application of a magnetic field  will undoubtedly be the materials of choice for future generations of solid state storage devices.  CaMn7O12 is a multiferroic where this coupling between electric and magnetic polarisation is particularly pronounced, and is reliant on an unusual form of orbital order.  On the other hand this coupling is absent in isostructural NaMn7O12 due to the subtle change in average Mn valence state.  We seek here to learn more about the nature of this coupling mechanism by studying the magnetic structures of the solid solution Ca1-xNaxMn3Mn4O12 and Ca1-xLaxMn3Mn4O12 by neutron powder diffraction.  Our results will show the nature of the magnetic ordering and how it is intrinsically linked to the charge and orbital ordering allowing new and improved multiferroics to be designed.
DOI: 10.5286/isis.e.rb1820601
title: What processes dominate porosity and structure evolution in Amorphous Solid Water (ASW)?

description: This experiment will measure the microstructure of Amorphous Solid Water (ASW), a porous material that can be formed by vapour-depositing water onto a cold plate, an excellent analogue of the ice found in star- and planet-forming regions of our galaxy. The thermal and temporal evolution of this metastable condensed-matter material has major implications in the physical and chemical role ices play in astrophysical environments. Our previous work on ISIS NIMROD has shown that the ASW has very small-scale porosity, and hints at larger scale structure of the material. With NIMROD data alone we are unable to elucidate whether the pores collapse or aggregate, a "hot" debate in the ice literature. This experiment tests ASW porosity scales and exploits the broad Q-range of SANS2d, with higher Q data providing a direct overlap to our earlier results obtained on NIMROD.
DOI: 10.5286/isis.e.rb1900110
title: Investigation of magnetic ordering in a new spin liquid candidate

description: PbCuTe2O6 consists of a 3-dimensional arrangement of spin-1/2 Cu2+ ions coupled by 3 interactions. The 1st neighbor interaction couples Cu2+ into isolated triangles, 2nd nearest neighbors form a highly frustrated hyperkagome lattice and the 3rd neighbor interaction couples them into antiferromagnetic chains. Muon spin relaxation and neutron spectroscopy suggest that spin dynamics persist down to 20mK without any indication of static magnetic order making it a potential candidate for spin liquid ground state. However, there is no concrete evidence for the absence of magnetic Bragg peaks in the system which is characteristic to the spin liquid state. Therefore, we wish to measure diffraction patterns of PbCuTe2O6 to confirm the spin liquid ground state and to investigate short range correlations as a function of temperature. Hence, we request two days of beamtime on WISH diffractometer.
DOI: 10.5286/isis.e.rb1910271
title: Extending the limits of experimental structure determination of amorphous substances -  the Ge-As-Se system

description: Ge-As-Se glasses are interesting for two main reasons: they are widely used in infrared optics and optoelectronics and they serve as model materials for theories of glass formation and stability (e.g. bond constraint theory). Therefore, detailed knowledge of their short range order is important both for applications and fundamental glass science/statistical physics. The main question is whether there are strong chemical correlations in these glasses (preferred bond types, e. g. Ge-Se bonds are more likely formed than Ge-Ge and Se-Se ones) or they can be described as random networks. Recently published experimental studies do not give a clear answer to this problem. The aim of our research is to determine the short range order in these glasses by combining experimental data from state-of-the-art neutron and synchrotron facilities.
DOI: 10.5286/isis.e.rb1910382
title: Understanding composition-driven anomalous tetragonality in a ferroelectric solid solution

description: The primary aim of this proposal to investigate a series of newly discovered Bi- containing ferroelectric systems based on Bi(MeMe)O3-PbTiO3 perovskite through studying their pair distribution function (PDF) as a function of composition and temperature to different local structural correlations that affect the properties of the system. Total scattering technique which renders pair distribution functions provides information on the local environment of each species which is crucial for ferroelectric systems since properties are mostly driven by local polarizations. We propose to use GEM instrument for this study, which is a dedicated instrument for the PDF measurements.
DOI: 10.5286/isis.e.rb1910530
title: Measurement of Residual Stresses on Samples Manufactured by Selective Laser Melting to Determine their influence on SCC in 316L SS

description: Selective laser melting (SLM) is an exciting and novel metal-based additive manufacturing process which offers numerous advantages over conventional material processing routes. The use of SLM is currently hampered by the lack of understanding and prediction capability of it's failure modes. SLM process simulations have been developed and sample orientation has been predicted to have an effect of the residual stress (RS). RS measurements are proposed in uniaxial samples built in 2 orientations  that will be used in stress corrosion cracking (SCC) experiments. Samples will be measured in their as-built condition and after heat treatment considered to mitigate RS. These measurements will help determine the role of RS in SCC of SLM components. In addition the measurements will provide validation for the SLM process and heat treatment simulation models developed at Imperial College London.
DOI: 10.5286/isis.e.rb1567513
title: Measurement of the proton radius from the hyperfine splitting energy in muonic hydrogen using muon spin repolarization
DOI: 10.5286/isis.e.rb1610034
title: High ethane/ethylene selectivity in ZIF-7@AC: A gate opening effect?

description: The main goal of the present proposal is to evaluate the high selectivity of a special type of MOF material (ZIF-7) confined in the cavities of nano porous activated carbons. Recent studies described in the literature have shown that ZIF-7 exhibits a high select¡vity towards ethane versus ethylene, although the exact mechanism of this selective adsorption is still unclear. Recent publications from the PI of the present proposal have shown that inelastic neutron scattering is a powerful tool to evaluate gate-opening phenomenon in this type of materials (ZIf-8 in this specific study) upon gas exposure. With this in mind, the main goal in the present proposal is to extend this evaluation to ZIF-7@AC materials upon exposure to several hydrocarbons. These results will provide some light into the structural flexibility of ZIF7.
DOI: 10.5286/isis.e.rb1610380
title: Determination of crystal field spectrum in terbium gallium garnet.

description: Magnetic frustration is the phenomenon of being unable to satisfy all magnetic interactions present in a system. It draws a lot of attention as it is the source of exotic behavior in many magnetic materials. Although it has been thoroughly studied in various groups of compounds, little progress has been made in its examination in the half-garnet lattice family, particularly terbium gallium garnet(TGG/Tb3Ga5O12). TGG is a promising candidate for hosting a magnetically frustrated spin liquid regime, but its existence in TGG has never been confirmed. Defining a crystal field scheme is a crucial, initial step in the investigation of any rare earth based magnet, and inelastic neutron scattering is the most reliable method of doing this. We propose a combined study at the LET and MARI instruments to observe, for the first time, the  full crystal field spectrum of the Tb3+ ions in TGG.
DOI: 10.5286/isis.e.rb1610456
title: Inelastic Neutron Scattering Experiments in the Sulfur-Ammonia Photothermochemical Cycle

description: The following proposal aims to ellucidate the role of ammonium ions in sulfite oxidation reaction. The key step in the sulfur-ammonia photothermochemical cycle, which is one of the potential processes capable to exploit a pollutant as sulfur dioxide to provide solar hydrogen at large scale and ammonium sulfate, an energy carrier, and a potential fertilizer respectively.Inelastic Neutron Scattering Experiments will be vital to monitor and label deuterated species at different stages of the abovementioned reaction, which in this particular proposal will be electrochemically induced. Thus, in principle, these experiments in tandem with Raman and Nuclear Magnetic  Resonance spectroscopy observations will confirm the participation of ammonium as an intermediate during water splitting.
DOI: 10.5286/isis.e.rb1610474
title: How an olefin adsorbs at a catalyst's surface and its implications to the chemical process

description: Metal and metal oxide nanostructures can be prepared in much different morphology (nanowires, nanobelts, nanofibres etc.) which are known to exhibit better adjustable properties in many fields compared to their conventional counterparts. As part of ongoing research in the development of more selective and efficient (overall greener) oxidation catalysts, the present proposal is part of a wider research programme (including funding grants). This proposal aims at understanding how a given reagent interacts with the catalysts surface in oxidation catalysis. A previous INS experiment has provided useful insights that deserve to be further explored. Results will contribute to establish a rational on how the mechanism works, especially why long induction periods are observed.
DOI: 10.5286/isis.e.rb1610481
title: INS study for the structural characterization of cellulosic nanostructured materials

description: As a response to fossil fuels scarceness and a growing awareness of environmental threats, the quest for sustainable alternatives to oil and oil-based products is a must. Alternative resources to current raw materials are sought by the industry. Cellulosic biomass meets the challenge as potential raw material, forming the feedstock for second-generation biorefineries. For this to be attainable, a better understanding on the cellulose fundamental structural aspects, which is very limited at present, should be pursued. In this study, natural cellulose will be studied using the sugar cane bagasse after the removal of the hemicellulose and lignin by hydrolysis reactions in a dilute-acid medium and at several reaction rimes in the range 0-60 min. Special attention will be devoted to the analysis of low frequency modes that should probe differences in the structural packing of cellulose.
DOI: 10.5286/isis.e.rb1610493
title: Influence of composition on fingerprint dynamics in cement-forming bioactive glasses.

description: Glass Ionomer Cements (GICs) - 2nd biggest earner of the British Technology Group - have found numerous applications in dentistry/medicine. The EU Commission in its advocating Hg-free dental/medical materials specifically highlight GICs as an excellent option; albeit currently too brittle for use as permanent implants. Lack of understanding of the influence of composition of the glass on its properties hinders materials optimisation. We look now to fill this void - our ab intio molecular dynamics determinations identify Al-centres as being candidate  controllers of flexibility/rigidity; in agreement with historic predictions. We propose to quantitatively characterise fingerprint dynamics of GIC glasses - helping resolve the bases of the composition-dependent dynamics, and their potential for promoting rigidity/flexibility at Al-centre, in the bulk and eventually the cements they form.
DOI: 10.5286/isis.e.rb1720076
title: Crystal and magnetic structures of Pb2-xBixMnO4

description: Manganese based oxides are of great interest for both spintronic and multiferroic applications.Pb2MnO4 crystallizes in the acentric but non-polar space group P-421c which allowspiezoelectricity. Pb2MnO4 shows antiferromagnetic order below TN = 18K. The magnetic spacegroup P-421c is compatible with piezomagnetism making Pb2MnO4 a candidate multipiezo(piezoelectric and piezomagnetic) material. However it is difficult to make dense Pb2MnO4 pelletsfor piezo- properties study. We have prepared a new solid solution Pb2-xBixMnO4 (x = 0 - 0.3). Bisubstitution significantly improves the sintering properties and dense pellets have been obtainedfor piezo- studies. We propose a powder neutron diffraction study on Pb2-xBixMnO4 at 5 - 300 Kon WISH to refine the magnetic and crystal structures, and detect any subtle magnetostrictioneffects from coupling between them.
DOI: 10.5286/isis.e.rb1720091
title: Host-guest interactions in flexible SMOFs

description: In the area of metal-organic porous materials, supramolecular metal-organic frameworks (SMOFs) constitute a blooming alternative. Their examples are still scarce when compared to MOFs (metal-organic frameworks), and there is not any study dealing with the crystallographic location of adsorbate molecules within the porous structure. In this proposal we aim to explore a family of SMOFs sustained by pi-pi; stacking interactions that are based on the assembly of wheel-shaped heptanuclear [Cu7(mu-H2O)6(mu-OH)6(mu-adeninato)6]2+ entities. These compounds experience expansion/contraction processes when exposed to different solvent molecules. Thus, we aim to analyse the flexibility of these structures when exposed to certain adsorbates (such as CO2 or H2O), in order to understand the structural changes taking place on SMOFs during the host-guest interaction (i.e. SMOFCO2/H2O).
DOI: 10.5286/isis.e.rb1720133
title: Structural and Magnetic Properties from Charge Orders in Iron Perovskite Oxides

description: Highly oxidized transition metal cations in oxides tend to display unusual electronic and magnetic behavior due to the highly covalent nature of the M-O interactions. Iron is of particular interest, because the charge instabilities associated with unusually high oxidation states are often relieved through charge transitions such as charge disproportionation (CD) and intermetallic charge transfer (CT). We recently reported the high pressure synthesis of a new perovskite Ca0.5Bi0.5FeO3 which successively exhibits a CD transition at 250 K and a CT transition at 200 K. Both transitions are coupled to changes in the structural, magnetic, and transport properties. Sr doping suppresses the CT transition while Co participates in the CT with possible high/low spin state changes. We propose to collect neutron powder diffraction data from Ca0.5-xSrxBi0.5FeO3 and Ca0.5Bi0.5Fe1-xCoxO3.
DOI: 10.5286/isis.e.rb1720182
title: Continued studies of the high temperature structural behaviour of Ca2Mn3O8

description: We recently synthesised a new layered manganes oxide with a frustrated connectivity of Mn4+ ions. Variable temperature studies demonstrated a deviation from linearity at approximately 472 - 573 K. We initially believed this to be as a result of cation hoping arising as a due to vacancy sites on both the A- and B-sites. Unfortunately our initial assessment of the transition temperature proved to be an over-estimation with the transition being closer to 423 K. Unfortunately in our previous neutron experiment we used the furnace and started data collection at 373 K This means we have insufficient data below the transition to fully characterise the origins of this. More recently we have been able to collect electrical data which also shows anomolous behaviour at ~423 K. We therefore propose to revisit our experiments over a more appropriate temperature range.
DOI: 10.5286/isis.e.rb1720247
title: In-situ neutron diffraction study on anomalous low-temperature micro-mechanical behavior of CoCrFeMnNi and HfNbTiZr high entropy alloys

description: During last decade, the appearance of high entropy alloys (HEAs) attracts so many attentions because of their unique phase structures and excellent properties.Very recently, a significant phenomenon was found in CoCrFeMnNi alloys. Generally, the fracture toughness of CoCrFeMnNi HEAs remains unchanged with decreasing temperature, while their strength shows an expected increase. Nevertheless, the underlying mechanisms remain unclear.Therefore, in-situ experimental investigation of the low-temperature deformation mechanism of HEAs is urgently required. In this proposal, we aim to trace the low-temperature deformation behavior of CoCrFeMnNi and HfNbTiZr HEAs in order to disclose the origin of excellent cryogenic mechanical properties in these alloys.
DOI: 10.5286/isis.e.rb1720399
title: The interaction of C6Hx (x = 6, 8, 10, 12) with Raney Ni

description: Fuels such as diesel contains different kinds of aromatic and poly aromatic compounds, which on their combustion emits environmental pollutants such as SOx, NOx, COx, and unburnt polycyclic aromatic hydrocarbons (PAH). These PAHs are not only environmental pollutants but are also increasingly associated with probable causes of several human diseases such as asthma and lung-cancer. Therefore, reducing the concentration of aromatic compounds in fuels during the refining process is of great importance. To attain this objective in this work, we would like to perform a detailed study on the fundamental interactions of benzene, cyclohexadiene, cyclohexene and cyclohexane on Ni as catalyst using Inelastic Neutron Spectroscopy (INS) and van der Waals Density Functional Theory (vdW-DFT). Here, we use the sequential hydrogenation of benzene as a relatively simple model for PAHs.
DOI: 10.5286/isis.e.rb1800000
title: Structure of two-component polymeric particles for enhanced optoelectronic performance
DOI: 10.5286/isis.e.rb1900135
title: How is the nanoscale structure of Amorphous Solid Water (ASW) impacted by the presence of adsorbates?

description: This experiment will  determine how the structure and porosity of Amorphous Solid Water (ASW) changes when the ice is contaminated by adsorbate molecules. ASW is a porous material formed by vapour-depositing water onto a cold plate, an analogue of the ice found in star- and planet-forming regions of our galaxy. Our previous work has shown that the ASW has very small-scale porosity, but NIMROD data of the pure water ice alone are unable to elucidate pore accessibility; open pores can trap volatile molecules well beyond their desorption temperature and therefore act as a reservoir for coolant molecules in star-forming regions. This experiment tests ASW porosity evolution as a function of ice-adsorbate morphology and measures ASW structural changes as the ice is grown and heated, exploiting the broad Q-range of NIMROD to probe the molecular level and meso-scale of the ice concurrently.
DOI: 10.5286/isis.e.rb1910008
title: Site-specific adsorption and local dynamics of water molecules in natural zeolite: the neutron Compton scattering view

description: Already in the low temperature region of water adsorption behaviour in natural zeolites, the faujasites, two important questions arise that require further investigation: (i) what is the most likely configuration of water molecules of tetrahedral symmetry inside the faujasite cages, and (ii) what is the possible role of nuclear quantum tunnelling (NQT) in the dynamics of confined water molecules. This proposal aims at shedding more light on these two important questions by performing Neutron Compton scattering (NCS) experiments on H2O confined in the NaY faujasite network across three temperature regions (i) liquid-to-liquid transition of water at 225 K,  (ii) fragile to strong water dynamics crossover, and (iii) water crystallization below 160 K, at three different water loading levels in the faujasite framework.
DOI: 10.5286/isis.e.rb1910174
title: Influence of path length on wavelength dependent transmission corrections for hydrogenous materials

description: Diffraction from hydrogenous materials is complicated by its large incoherent scattering contribution. For many materials, deuteration before performing experiments is the solution. For many systems this is not possible, due to incomplete deuteration, cost and/or changes to the structure and/or phase transitions that are of interest. For TOF methods, the situation is further complicated by the energy dependence of the incoherent scattering cross-section, meaning that both transmission and multiple scattering corrections are energy dependent. This proposal continues on the previous work (RB1810041) to investigate the effects of path length using powders and a well defined H-content liquid for absolute comparisons, which we were unable to attempt due to time constraints. The aim is to generate empirical curves for data correction of TOF diffraction data at ISIS and other pulsed sources.
DOI: 10.5286/isis.e.rb1910230
title: Unveiling molecular and collective magnetism in the coupled trimer spin system Ba4NbMn3O12

description: When isolated spin clusters are weakly coupled to each other, zero-dimensional quantum and three-dimensional collective magnetism concomitantly occur. This is envisioned in the low-lying magnetic excitations, including transverse and longitudinal magnon modes. The newly discovered hexagonal perovskite Ba4NbMn3O12 constitutes Mn3O12 trimers made of three face-sharing MnO6 octahedra, with the trimers arranged in triangular planes. Each Mn3O12 trimer is corner-shared with the non-magnetic NbO6 octahedra, thereby leading to weak intertrimer interactions through the Mn-O-O-Mn super-super-exchange paths.  In addition, adBa4NbMn3O12 shows a ferromagnetic type order at 42K, yet with a small negative Curie-Weiss temperature of -4K. This energy hierarchy renders Ba4NbMn3O12 an attracting platform to explore a crossover of molecular magnetism to more collective behavior.