cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1820148
title: Complex ordering in a new polar A-site deficient perovskite

description: Recent theoretical work has identified that oxygen octahedral rotations (OORs) in layered perovskites such as Ruddlesden-Popper (RP) phases can generate noncentrosymmetry (piezoelectricity or ferroelectricity) by a hybrid improper mechanism. Our group has reported OOR-induced noncentrosymmetry in RP NaRTiO4 (R = rare earth) [Phys. Rev. Lett. 112, 187602 (2014)]. We now extend our understanding of OORs to A-site deficient perovskites, R1/3TaO3, that exhibit a layered ordering of the R cations and vacancies. Although the crystal structure was previously reported for R = La-Tm, no reliable crystallographic data are available for Y1/3TaO3. We here propose variable-temperature neutron powder diffraction experiments for Y1/3TaO3 to resolve unambiguously the OOR pattern in the room-temperature phase and also to identify the high-temperature incommensurate structure due to the OOR frustration.
DOI: 10.5286/isis.e.rb1820205
title: Interplay between magnetism and superconductivity in the FeYSr2Cu2Oy iron substituted cuprate

description: We want to address the problem of a possible coexistence of superconductivity and magnetism in the FeSr2YCu2Oy cuprate by means of a combined ZF/TF-muSR study. This compound presents a laminar ordering of copper and iron along the crystallographic c axis, allowing the study of the iron oxidation state effect in the superconducting and magnetic properties of this material. We have observed a progressive evolution from a magnetic parent compound at low doping levels to a bulk superconducting phase after ozone treatment. We aim here to characterize by ZF-muSR the temperature and doping dependence of the magnetic interactions, in order to resolve whether these interactions precede or compete with superconductivity. For this purpose, the real superconducting volume fractions are to be also determined by a TF-muSR measurement of the magnetic penetration depth.
DOI: 10.5286/isis.e.rb1820288
title: Interactions of lipidic cubic nanoparticles with model lipid biomembranes at the air water interface

description: Lipidic cubic nanoparticles (LCNPs) have been extensively studied as therapeutic agents and delivery systems due to their biocompatibility, ease of drug encapsulation and targeting. Better understanding of the interplay between LCNPs and model lipid membranes is needed in order to exploit their use in clinical applications. We have shown that less condensed layers facilitate incorporation of the LCNPs material while highly organized layers keep the LCNPs intact and outside the monolayer, but specific information about the structure and composition of the system is missing. We propose to characterize the interactions of LCNPs at 2 surface pressures and with 2 different lipid monolayers (acting as simplified models of healthy and cancer cell membranes) using neutron reflectivity. Information about lipid exchange and particle attachment will pave the way for future drug release studies.
DOI: 10.5286/isis.e.rb1820535
title: Load partitioning analysis for duplex steels and the evolution of change in reference lattice parameter D0 with increasing plastic strain

description: We aim at modelling the effect of local phase-specific micro residual stresses on the residual stress evaluation for multiphase materials and plan to study the effect of local distributions of micro residual stresses on the lattice parameter D0. In this regard the generation of phase-specific residual stresses will be studied in detail for two fine grained duplex steels with varying content of the two dominant phases by means of neutron diffraction analysis of the load partitioning behavior. For this in-situ strain analysis will be carried out for cylindrical tension/compression samples using TOF neutron diffraction at ENGIN-X up to large plastic strain. Further, D0 will be determined for the same material states for small cuboid samples (sectioned by EDM) with variation in their cross section area. By this means the sample size effect on the D0 distribution will be analyzed. The samples
DOI: 10.5286/isis.e.rb1900033
title: Total scattering measurements for local structure determination in novel reduced activation high-entropy alloys for fusion

description: Nuclear fusion offers safe and sustainable power generation, without the production of long-lived radioactive wastes. Fusion core structural materials will be subjected to neutron fluxes greater than in current nuclear fission reactors, as well as extreme heat loads, and the search is on to find the most appropriate material. High Entropy Alloys (HEAs) are a combination of several elements in similar amounts. Some HEAs have a number of attractive properties, including radiation resistance. We have recently produced novel radiation damage resistant HEAs for fusion, but identifying their crystal-structures using our laboratory equipment is difficult due to the similarity of the elements used. Therefore, in order to determine why our HEAs are so resistant to damage, we need to characterise the alloys using neutrons to obtain a more accurate picture of the arrangement of the atoms.
DOI: 10.5286/isis.e.rb1900058
title: ChipIR commercial access: ARISTA #3

description: Arista Networks December 1-4th (3rd of 2018) commercial access to ChipIr beamline.
DOI: 10.5286/isis.e.rb1620356
title: Revealing the structures of porous liquids

description: New technological advances require new types of materials. For example, currently there is no economical technology for capturing carbon dioxide released from power plants. We have recently invented a new type of material, called a porous liquid. As its name implies, this material is a liquid which contains tiny microscopic holes, each about the size of a single molecule. The liquid can absorb large amounts of gas into these holes. Therefore, we hope that such a material might ultimately help to solve problems such as carbon capture. Before we can find applications for this new type of material, we need to understand it in more detail. For example we need to know exactly how the gas molecules are distributed throughout the liquid. The experiments that we will perform will tell us this information which will help in the process of developing these materials towards applications.
DOI: 10.5286/isis.e.rb1700065
title: Characterization of the High-Energy Neutron Beam of the ChipIR beamline using a CCD at 800 MeV

description: Flux Measurements of the High-Energy Neutron Beam of the ChipIR beamline using a CCD at 800 MeV
DOI: 10.5286/isis.e.rb1700072
title: Upsets induced by neutrons in next-generation Flash Memories

description: Flash memories are the electronic component in which the feature size is scaled more rapidly and which have the largest capacity among semiconductor devices. Recently, another solution besides scaling has been pursued to increase density, i.e. vertical integration, with cells stacked in a complex 3D structure.  We plan to irradiate next-generation Flash memories at ISIS, to study the response of these devices to the neutron beam provided by the ChipIR line, which reproduces the terrestrial neutrons spectrum with several orders of magnitude of acceleration, if available, or the VESUVIO line. Samples with both conventional planar and 3D NAND architecture will be exposed to neutrons and results will be compared with those previously obtained at VESUVIO. The analysis will be focused on Floating Gate (FG) errors and multiple bit upsets.
DOI: 10.5286/isis.e.rb1710161
title: Polarized neutron reflectivity investigation of Fe+ ion irradiated FeCr films

description: For Fusion energy applications FeCr ferritic martensitic steels are candidate structural materials due to their radiation resistance and good mechanical properties. Thus, the understanding of the neutron irradiation effects on FeCr steels is of paramount importance for the development of radiation resistance materials. The damage induced in the material by fusion neutrons of 14 MeV can be imitated employing self-ion irradiation. Previous PNR measurements of Fe+ ion irradiation of Fe films have shown enhancement or reduction of the Fe magnetic moment depending on the type of defects created, i.e. vacancies versus interstitials. With the current proposal we aim at investigating the induced magnetic effects on FeCr films employing polarized neutron reflectivity measurements.
DOI: 10.5286/isis.e.rb1710218
title: Assembling floating, very sparsely tethered, protein-lipid bilayers.

description: We have recently used Polref in to measure the assembly of tethered floating lipid bilayers. These are useful models of biological membranes in which a phospholipid bilayer is tethered to a solid surface by a molecular linker.  The length of this linker can control the width of the water gap between the surface and the floating bilayer. Since they are easy to make and characterise , they promise an additional method to help us build accurate models of bacterial outer membranes. Here the water gap represents an important cellular compartment called the periplasm.  Our previous POLREF experiments showed that we can assemble bilayers at very low tether densities which is important to minimise their effect on the membrane. Here we wish to show that we can insert and characterise proteins within the lipid bilayer which is another important step in creating useful models of living membranes
DOI: 10.5286/isis.e.rb1710300
title: Ex situ Study of glass formation from ion-exchanged Zeolite by INS

description: This proposal is a continuation of Rapid Access experiment RB170007 done on MARI in September 2016, as recommended by MARI beam scientists. This experiment was done to establish the collapse of ion-exchanged zeolites to form amorphous materials was equivalent to earlier measurements conducted on zeolite Y using MARI. This new experiment is meant to discover what changes occur in the low frequency vibrations when different types of ion-exchanged cations are used like Nd and Cu compared to standard zeolites where charge compensation is achieved using Na or H. The results of the rapid access experiments so far showed high agreement with the Science paper published in 2005. So we can be sure that the sample handling process is fine for the experiment. After discussion with the beam scientist, we both agree that it is better to apply for continuation of the original experiment.
DOI: 10.5286/isis.e.rb1710406
title: Nanostructuring of Polyphilic Liquid Crystals

description: The organisation of molecules in liquid crystal phases relies on many factors, often related to space-filling considerations driven by the volume of different molecular fragments. However, in systems that contain, for example, hydrocarbon and fluorocarbon chains, the mutual immiscibility of the fragments can drive the system into higher degrees of order. In collaboration with Pace and Pibiri in Palermo, Italy, we are preparing and characterising (through a joint student) the behaviour of polyphilic compounds that contain hydrocarbon, fluorocarbon and charged segments. The ordering is a function of the need for all three different fragments to be located close to another like fragment, but from the preliminary data available from small-angle X-ray scattering, the nature of the organisation is not clear. SANS experiments offer the possibility to unravel the details of the nanostructuring.
DOI: 10.5286/isis.e.rb1710420
title: Unravelling the solution structures and stability of industrially-important antibodies with and without glycans

description: The glycosylation of glycoproteins is a major determinant of their stability, and glycans also affect their aggregatibility (precipitation). An understanding of this is essential for improving manufacturing processes. Our extensive background in glycosylation and scattering (see below) indicates that we are ideally positioned to investigate antibody glycan structures in detail. We will compare both glycosylated and deglycosylated IgG antibodies using a combination of neutron and X-ray scattering, ultracentrifugation and modelling. The two overall aims of this project are to (i) identify how the solution properties of glycans affect antibody manufacture and (ii) develop a pipeline of new methods for the rapid atomistic modelling of antibody conformations based on neutron and X-ray scattering fits in order to evaluate the manufacturability of variously glycosylated antibodies.
DOI: 10.5286/isis.e.rb1710426
title: Investigating the excitation spectrum of a single-band Hubbard model compound NaCuF3

description: The single band Hubbard model is considerably the simplest  effective model that includes both the delocalizing/hopping energy and the on-site interaction for describing strongly correlated electron system. Despite the simple form, it is still yet challenging to find the solution to the model. Here we propose to investigate the energy spectrum of the compound NaCuF3 which could be a condensed-matter realization of the single band Hubbard model, as suggested by recent  ab initio electronic structure method calculation.
DOI: 10.5286/isis.e.rb1720266
title: Mixed Amino-Acid Based Surfactant Monolayers

description: Amino acid based surfactants have been known for many years but so far few detailed studies have been carried out on their properties. We are using amino acids extracted from grain residues, otherwise used in animal feed, to prepare surfactants with amino-acid based headgroups. We aim to evaluate whether such feedstocks could provide a renewable source for such amphiphiles for use in emulsification, and formulations for delivery of active species. A preliminary reflectivity study using neutron and Xray reflectivity to study 1:1 mixtures of monolayers of three amino acid based surfactants found evidence of interesting interactions between headgroups leading to marked alteration of monolayer structures. Here we wish to extend this study to other molar ratios to better understand the interactions between these species, and also to complete characterisation at different temperatures.
DOI: 10.5286/isis.e.rb1810153
title: Structure of sodium calcium magnesium polyphosphate glasses

description: Phosphate based glasses, are being developed to replace the current silicate based systems as biomaterials. For application as biomaterials, beneficial ions can be added to these glasses and their release profiles can be compositionally controlled. Magnesium ions are crucial for bone regeneration and their concentration can directly affect bone strength. The proposed work will use neutron scattering methods to study the structure of a series of complex sodium calcium magnesium phosphate glasses being evaluated as potential biomaterials. In particular we see to establish the coordination environment of the magnesium ions which have an important influence on the strength of the glass and its solubility.
DOI: 10.5286/isis.e.rb1810175
title: Determination of Organic Friction Modifier conformation under shear

description: Engine oils act to lubricate and protect moving parts in an engine. They act to reduce friction and reduce emissions. A major class of friction reducing additives are organic friction modifiers (OFMs) and these molecules are known to associate with the metal surfaces, although their exact conformation remains unknown. To answer the question about OFM conformation, we have commissioned a new tribometer rig which allows neutron reflectivity experiments to be carried out, at elevated temperatures and pressures, whilst the surface is being sheared. In this set of experiments, we will measure the conformation of glycerol mono-oleate molecules on iron oxide surfaces at a range of shear rates for two different pressures.
DOI: 10.5286/isis.e.rb1810476
title: Conduction Pathways in Alkali Lanthanide Pyrosilicates, A3LnSi2O7

description: Alkali Lanthanide Pyrosilicates (general formula = A3LnSi2O7) are promising candidates for use as solid electrolytes in all solid state Li-ion and Na-ion batteries. To date the structure of Li3LnSi2O7 has not been reported. We have synthesized powder samples of A3LnSi2O7 (A = Li, Na; Ln = Gd-Er) and characterized them by powder X-ray diffraction and impedance spectroscopy. For a full analysis of the crystal structure of A3LnSi2O7, we require neutron powder diffraction to determine the position of the Li, Na, Si, and O atoms in the presence of the heavy Ln atoms; and neutron total scattering to study the effect of alkali ion site disorder on the alkali ion conduction mechanisms in the lanthanide silicate framework.
DOI: 10.5286/isis.e.rb1810830
title: µSR study of the magnetic ordering in the S=1 linear chain compound KNiCl3.

description: We propose to continue our study of KNiCl3, a 1D S=1 linear chain compound. Our previous work has shown evidence for two magnetic transitions between 2 and 15 K. Experiments at PSI have allowed us to coarsly track this out, however from the muon spin rotation frequency and the damping, these should also be within the ISIS time regime. Therefore we seek to complete our study to extract the order parameters for these transitions using the MUSR spectrometer.
DOI: 10.5286/isis.e.rb1810857
title: Low temperature phases of WO3  a reinvestigation

description: WO3 is an important technological material with wide usage in gas-sensing devices but its low temperature phases are still mysterious. There are conflicting reports in the literature and new predictions from Density Functional Theory calculations which motivate us to clarify the situation experimentally using HRPD. We will investigate the structure between room temperature and 5 K to clarify the phase transitions and detailed nature of the structural distortions. This will allow us to understand better the driving mechanisms behins structural changes in WO3 and therefore also the fascinating and useful physical properties it hosts.
DOI: 10.5286/isis.e.rb1820179
title: Hydride-ion mobility analysis of SrVO2H using quasielastic neutron scattering

description: The proposed experiment at ISIS aims at the characterization of the diffusional motion of the hydride-ions in SrVO2H, which possesses the highest H (hydride) content among transition metal oxyhydrides. SrVO2H is derived from the simple, cubic, perovskite SrVO3. As a peculiarity, the mixed O2-/H- anion arrangement in SrVO2H is fully ordered and its structure is tetragonal displaying alternating sheets of VO2 and SrH along the tetragonal axis. The elucidation of the diffusional properties of hydride-ions in SrVO2H from QENS measurements will give new fundamental understanding of transition metal  hydrogen diffusion in elusive perovskite transition metal oxyhydride materials.
DOI: 10.5286/isis.e.rb1820234
title: Direct observation of type-2 cycloidal ordering in BiFeO3 thin films under tensile strain

description: BiFeO3 (BFO) is the model and most promising multiferroic material as both ferroelectric and magnetic orders coexist at room temperature. In order to exploit his functionalities in modern devices, one needs to understand how these orders and especially its complex magnetic structure made of a G-type antiferromagnetic order superimposed with a cycloidal modulation (62 nm) are affected in thin film form. Up to know, most of the experimental works (including ours) have been done in the compressive strain where the cycloid has been shown to extend its period with misfit strain until disappearing at high strain. In contrast, reports on the tensile strain side are scarce despite the magnetic richness. Indeed, we theroetically showed that BFO under tensile strain exhibits another cycloidal modulation we want to address by determining its propagation vector and period in this proposal.
DOI: 10.5286/isis.e.rb1820335
title: Adsorption Structures of Organics additives at the Iron/Oil Interface and the Role of Water

description: Numerous chemical additives have been added to steel surfaces to improve adhesion, and prohibit corrosion if the substrate is reactive to its surrounding environs. This experiment will investigate the monolayer structures of key adsorbates, that are known (from our experiments) to adhere well to an iron surface and act as adhesion promotors, and corrosion inhibitors. The adsorbates are chosen as a key reagent in the coatings industry, and/or as a key functional groups with particular affinity to the iron surface.. To capture the key behaviour of the additives at the steel-oil interface, the additives are to be adsorbed from dry oil. Then the changes in additive behaviour in wet oil will be investigated to observe the role of water in the additive adhesion process.
DOI: 10.5286/isis.e.rb1820529
title: Continue improving reliability of residual stress characterization in dissimilar metal welds

description: The proposed experiment is the final experimental step for validating the measurement methods and analytical models developed based on the systematic experimental studies (RB1720433-ENGIN X, Stress-Spec and SALSA) with an aim to improve the reliability of neutron diffraction technique in characterizing residual stress in dissimilar metal welds (DMWs). In this experiment, we plan to measure an industrial DMW sample having a more complex joining interface compared to the previous studies (orthogonal interface), and continue the process of developing the methodology for quantifying and correcting the errors (pseudo-strains) as a result of the gauge volume traversing an internal boundary. A cross-technique validation approach will be adopted using other residual stress characterization technique(s) for complementing the results from the developed methods.
DOI: 10.5286/isis.e.rb1820626
title: The structure of metal metaborate glasses

description: Scientific studies of borate glasses tend to focus on alkali borates, which can be made over a wide and continuous composition range. Contrastingly, metal borates have a wide immiscibility region at low to medium metal content in which glasses cannot readily be made. Nevertheless, metal borate glasses are more important for many potential applications. Metal borates, however, can be made as glasses at the metaborate composition, and we will investigate the structure of 9 different metal metaborates. We will investigate the likely relation between the fraction of 4-coordinated boron atoms and the cation field strength of the metal cations.
DOI: 10.5286/isis.e.rb1620038
title: Local structure variation of polar nano-regions in ultrahigh piezoelectric relaxor-PbTiO3 materials

description: Relaxor ferroelectrics are a class of locally disordered crystals possessing peculiar structure and electrical properties. The solid solution of a relaxor perovskite and PbTiO3 (relaxor-PT) exhibits ultrahigh piezoelectric coefficients and electromechanical coupling factors. In order to fully understand the structural origin of this special class of materials' outstanding properties, we propose to carry out a series of low-temperature neutron total scattering experiments and utilize pair distribution function analysis techniques, aiming to investigate the local structures, especially the local polar directions within the polar nano-regions. We will also verify the evolving of the polar nano-regions with increasing temperature, and link them with the change of the electric properties.