Global warming is a current hot topic due to its potential for irreversible environmental damage. Ambitions were made within the Paris agreement to limit the temperature rise to be below 1.5 ºC pre-industrial level. Alternative fuel sources are needed to replace fossil fuel, reducing the emission of greenhouse gases including CO2. Hydrogen gas is one popular choice to replace fossil fuels, due...
Quokka was the first Small Angle Neutron Scattering instrument to be in operation at the Australian research reactor, OPAL [1]. It is a 40 m pinhole instrument operating with a neutron velocity selector, an adjustable collimation system providing source-sample distances of up to 20 m and a two dimensional 1 metre square position-sensitive detector, capable of measuring neutrons scattered from...
The time-of-flight direct-geometry neutron spectrometer, Pelican, has been in user programme since 2014 at the OPAL research reactor, at the Australian Nuclear Science and Technology Organisation (ANSTO). The Pelican instrument was designed to meet the diverse requirements of the Australian scientific community from physics, chemistry, material science, to biology. A wide range of research...
Wombat is a high intensity neutron diffractometer located in the OPAL Neutron Guide Hall. It is primarily used as a high-speed powder diffractometer, but has also expanded into texture characterisation and single-crystal measurement. The high performance comes from the combination of a high speed area detector with a large beam guide and correspondingly large crystal monochromator. Wombat can...
The Echidna high-resolution powder diffractometer remains a reliable and productive ACNS instrument contributing annually to about 50 published studies done on a wide range of topics, from magnetic, energy and planetary materials to cultural heritage and additive manufacturing. We will discuss how Echidna has been affected by COVID-19 measures, latest and planned developments, user programme...
The direct geometry, time-of-flight spectrometer Pelican has been in the user programme since October 2014 at the OPAL research reactor at the Australian Nuclear Science and Technology Organsiation (ANSTO). Situated on the cold guide CG1, Pelican is suited to measuring low energy excitation's from varying materials. This encompasses phenomena that are as diverse as the diffusion of water in...
Tracking Changes in porosity at realistic underground conditions is of great scientific and technological interest to the resource industry, underground aquifer management, and material science, to name a few. Small Angle Neutron Scattering (SANS) and Ultra-Small Angle Neutron Scattering (USANS) are complementary techniques that can non-destructively investigate open and closed pore structure...
The purpose of the scientific computing support at ANSTO is to aid in the interpretation of both
structural and dynamical data from the neutron scattering instruments using atomistic modelling
calculations. Most of these calculations are done with ab initio scientific software packages based on
Density Functional Theory, including VASP, WIEN2K, ABINIT, SIESTA, PHONON, and QUANTUM
ESPRESSO,...
The Australian Centre for Neutron Scattering offers neutron spin filters for six instruments (WOMBAT, PELICAN, QUOKKA, PLATYPUS, TAIPAN and SIKA), using a combination of supermirrors and polarised $^3$He cells. The infrastructure required to use $^3$He spin filters is particularly complicated, and a clear understanding of this is pivotal to designing and carrying out successful experiments...
Direct Laser Melting (DLM) deposition is an additive manufacturing technique in which a high power laser is used to create a melt pool on a workpiece while a jet of metal powder is applied, resulting in localised material deposition. This technique is used in industry for additive repairs, cladding with dissimilar metals, or, in conjunction with a CNC milling machine, as a full-fledged 3D...
ANSTO for more than ten years successfully operates Small Angle Neutron Scattering (SANS) instrument Quokka [1] and in 2016 commenced user operation of the second SANS instrument, Bilby [2]. Ultra-small angle scattering machine Kookaburra [3] is completing the set of the SANS instruments at ANSTO.
Bilby exploits neutron Time-of-Flight (ToF) to extend the measurable Q-range, over and above what...
In this presentation, we will show the Taiwanese built cold-neutron triple-axis spectrometer SIKA at ACNS which was funded by the Ministry of Science and Technology (MoST), Taiwan. We are now running the user program since 2015 with over 20 papers published since then. The cold-neutron triple-axis spectrometer SIKA excels at measuring well-defined regions in S(Q, ω) space with very low...
The Australian Centre for Neutron Scattering at ANSTO hosts a suite of four inelastic neutron spectrometers for investigating dynamics in materials over a variety of energy scales (up to 200 meV) and energy resolutions (down to 1 μeV). The thermal spectrometer, Taipan, has operated as a triple-axis spectrometer since 2010, and more recently from 2016 it has also incorporated an alternative...
PLATYPUS is the initial neutron reflectometer at the Australian Centre for Neutron Scattering with the capability to study surface and interface systems ranging from biomolecules, soft matter through to magnetic thin films [1-3]. There have been a number of significant improvements to both the instrument and data reduction and treatment software [4] over the last two years. On the hardware...
The program CRYSOL1, was the first method developed to rapidly calculate small-angle scattering (SAS) profiles from atomic coordinates of biomolecules. It was a major breakthrough, providing the missing link between high-resolution structures and solution SAS data. The importance of this breakthrough is evident in the fact that decades later, alternate methods continue to be...
Epidemic thunderstorm asthma (ETSA)[1] is associated with inhalation of airborne pollen grains and aerosolized pollen fragments, causing hypersensitive immune reactions[2] that might lead to an asthma attack. The wall of pollen grains (intine) contains cellulose which is hypothesized to initially interact with the nasal and tracheal mucous layer[3] when inhaled. The air-way mucous layer is...
All living organisms rely on membranes that act as selectively permeable barriers controlling movement in and out of cells. Model systems such as tethered-bilayer lipid membranes (tBLMs) can be designed to replicate the fundamental structure and function of their biological counterparts. This creates a simplified pathway for determination of the effects that antimicrobial medicines can have on...
K. Chea a, C. Garvey b, W. van Megen a and G. Bryant a
a School of Science (Physics), RMIT University, Melbourne, Australia.
b Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia.
The fundamentals of crystallisation and glass formation in atomic systems are not yet fully understood. Hard-sphere colloidal nanoparticles have been shown to be promising model systems...
Lithium garnet oxides have been put forward as a solid-state alternative for Li-ion electrolytes since the Li$^{+}$ conducting abilities of Li$_{7}$La$_{3}$M$_{2}$O$_{12}$ (M = Ta, Nb) was discovered in 2003. [1] These solid state materials exhibit physical and chemical properties desired for more efficient and safer Li-ion battery electrolytes. [2] Lithium garnet oxides can exist in...
Poly(3,4-ethylenedioxythiophene) (PEDOT) is a widely used conductive polymer material for organic thermoelectric device, stretchable bioelectronics, optoelectronics and so on. Its success is largely attributed to the availability of the polymer dispersion. Recently people try to decipher the highly conductive nature of the PEDOT:PSS hybrid from molecular assembly with structural hierarchy....
Neutron tomographic, texture and phase analyses undetaken on the Neutron Beam Instruments Dingo, Kowari and Echidna have been employed to investigate plated silver coins minted in Athens and in the Greek colonies of Kroton and Metapontum (Southern Italy) during the 6th and 5th centuries BC. The investigation aims to define the plating method by characterising the manufacturing conditions and...
Lanthanoid Single Molecule Magnets (SMMs) are molecular materials that exhibit slow relaxation of the magnetisation of molecular origin, thus showing promise for a wide range of technological applications, such as spintronic devices, qubits for quantum computers and molecular memories. The origin of the energy barrier to the reorientation of the magnetic moment in a lanthanoid SMM lies in the...
The magnetism of porous coordination polymers is of long standing interest as changes to the hydration level of the pore have been shown to drive small changes in the structure of the framework, which in turn give rise to large differences in the magnetic properties. This capacity for magneto-structural correlations naturally leads to ideas such as utilising these properties as a magnetic...
The polarised neutron reflectometry (PNR) technique measures the magnetic depth profile with nanometre-scale resolution in thin film structures. Although the raw experimental data can a rich source of qualitative information, to extract the full quantitative details, the experimentalist must solve the inverse-problem by postulating models to fit the data to yield the full set information. In...
A growing reliance on critical transport infrastructure combined with the dependence upon railway for mining and mineral export has heightened operational requirements and lead to premature failure of rail components under severe loading conditions caused by plastic deformation, rolling contact fatigue and accelerated wear rates. Rail replacement is a costly and disruptive undertaking...
Lithium-ion batteries (LIBs) form an important part of our daily life, powering portable electronic devices, as well as electric and hybrid electric vehicles. However, the limited energy density of current LIBs results in their failure to meet the increasing requirements of rapidly developing technologies. Since the performance limitation in existing LIB technology is the cathode, exploring...
Explosive energy conversion materials with extremely rapid response times have a diverse and growing range of applications in energy, medical, and mining areas. Research into the underlying mechanisms and the search for new candidate materials is so limited that Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 is still the dominant material after half a century. In this work, we report the discovery of a new,...
The quaternary semiconductor Cu2ZnSnSe4 (CZTSe) is a promising environment-friendly and low-cost material as a solar cell absorber layer with a power conversion efficiency of 11.6%. Its photovoltaic performance is currently limited due to its disorder between the Copper & Zinc lattice sites, which creates band tailing and creates voltage deficit. By replacing Cu in CZTSe with isovalent Ag,...
Transition metal oxides represent a wide set of materials with a broad range of functionalities which can be tuned by the careful choice of parameters such as strain, oxygen content, and applied electric or magnetic fields. When the material exhibits more than one primary ferroic ordering- ferromagnetism, ferroelectricity, ferroelasticity or ferrotoridicity in the same phase, it becomes...
Solid oxide fuel cells (SOFCs) offer clean alternatives to current carbon emitting energy sources; however, reducing their operation temperature is a major challenge for widespread application. Hence, the development of novel electrolyte materials with high room temperature ionic conductivity is crucial. Pyrochlore oxides, of the general chemical formula A2B2O7, exhibit chemical and structural...
We applied neutron diffraction and positron measurements to estimate the vacancy of CoCrFeNi and CoCrFeMnNi high-entropy alloys (HEAs) using Cu as a benchmark. The corresponding formation enthalpies and associated entropies of the HEAs and Cu were calculated. The vacancy-dependent effective free volumes in both CoCrFeNi and CoCrFeMnNi alloys are greater than those in Cu, implying the easier...
Layered oxides based on first-row transition metals dominate cathode materials for commercial batteries and remain highly interesting as well as challenging in their structural study during electrochemical reactions. Neutron diffraction is a powerful method to obtain periodic structural information complementary to that obtained by X-ray diffraction. Although inferior to X-ray diffraction in...
Carbon-neutral energy generation is being developed in order to combat climate change. Two technologies of current interest, which are related to renewable and nuclear energy respectively, are next-generation oxygen-ion conductors for fuel cells and materials suitable for long-term storage and disposal of radioactive nuclear wastes [1-2].
Pyrochlores of the structure $A_{2}B_{2}$O$_{7}$ have...
The development of new solid electrolytes is becoming increasingly important, e.g. in rechargeable batteries for electric vehicles, where current organic electrolytes cause major safety concerns. The ABO3 perovskite metal oxides have shown excellent lithium and sodium ion conductivity owing to their stability and structural flexibility. This has led to the development of several...
Interactions at interfaces of magnetic materials such as giant magnetoresistance (GMR) form the physical foundation of many technological devices in today's market. Although GMR technlogies are now somewhat dated, interactions at the interface between layers of oxide materials continue to demonstrate attractive mechanisms for technology applications due to the wide variety of available oxide...
Crystal field theory, invented in the 1930s by Hans Bethe, provides an explanation of the crystal field excitations (CFE) observed in inelastic neutron scattering (INS) spectra of rare-earth compounds [1]. However, some long withstanding problems remain. Our inelastic neutron scattering experiments on vanadates CeVO3 and TbVO3 did reveal an unexpected large shift of the energies of the crystal...
Methanol-water mixtures are known for their unusual thermodynamic behaviour. On varying mixture composition, the thermodynamic properties do not vary linearly. This is attributed to the formation of structures at a molecular length scale, called as micro-phase. When formaldehyde is solvated in methanol-water mixtures, its chemical and physical behaviour is very much dependent on its...
Li3Co2SbO6 has been synthesized using high temperature solid-state methods. Li3Co2SbO6 is found to adopt two highly distinct structural forms: a pseudohexagonal (monoclinic C2/m) layered O3-LiCoO2 type phase with “honeycomb” 2:1 ordering of Co and Sb, and an orthorhombic Fddd phase, isostructural with Li3Co2TaO6 but with the addition of significant Li/Co ordering. Pure samples of both phases...
From literatrure reports, Fe-Pd alloys in the vicinity of Fe-30at%Pd exhibit two martensitic transformations on being cooled from just above room temperature to about 100K. A preliminary study of a large single crystal of this composition at the KOALA beamline, not only showed evidence for these transformations but also revealed most interesting satellite reflections around certain Bragg...
A skyrmion is a topological stable particle-like object comparable to a spin vortex at the nanometre scale. It consists of an about 50 nm large spin rotation and its spin winding number is quantised. Skyrmions emerge in chiral crystals as the result of competing symmetric exchange and asymmetric Dzyaloshinskii-Moriya (DM) interactions and typically form two dimensional hexagonal lattices...
In 1912, Max von Laue first demonstrated atomic diffraction produced by passing a beam of polychromatic X-rays through a single crystal [1], and was awarded the Nobel Prize for Physics two years later for his discovery. Laue diffraction, as this phenomenon was later called, was also demonstrated with neutrons [2], shortly after the pioneering monochromatic experiments by Schull and co-workers...
The high cost, low yield and inconsistency of crystal growth are among the main obstacles for the introduction of new materials to widespread application in various detection devices. In-situ diagnostics during crystal growth can be very helpful for the optimization of the growth process of a specific material. Neutrons appear to be unique probes providing information on the distribution of...
The Beryllium Filter Spectrometer (BeF) is one of the inelastic neutron spectrometers located on Taipan, the other being a classical thermal triple axis spectrometer (TAS). The BeF is ideal for vibrational spectroscopy investigations on a molecular level. In particular as the total scattering cross-section of hydrogen is about 82 barn, which is mainly due to incoherent nuclear scattering from...
Surfaces covered with densely tethered polymer chains possess desirable properties and are ubiquitous in natural and human-made systems. These properties stem from the diffuse structure of these polymer brush interfaces; consequently, resolving their structure is key to better understanding and designing polymer brush systems. We have been using the PLATYPUS neutron reflectometer at the ACNS...
In recent years, compounds with chiral structures have attracted much attention mainly because of noncollinear and non-coplanar spin textures, which have an important application in spintronics. In chiral compounds, the lack of inversion symmetry can give rise to an asymmetric spin interaction, the so-called Dzyaloshinskii-Moriya interaction, which contributes to the symmetric exchange...
refnx [1] is a next generation reflectometry analysis package, building on its predecessor, Motofit. In this presentation we discuss its main design features:
- Bayesian statistics core with comprehensive uncertainty analyses and model selection ("how many layers can the data justify") [2].
- modular construction of structural models, ranging from a basic Slab up to freeform SLD profiles...
This poster will highlight some resent additions to improving the spatial positioning of samples on the Kowari instrument for residual stress measurement. This includes cross laser reference point positioning at both 45 and minus 45 degree to the primary beam. In addition the new ATOS GOM structured light scanning system will be described with a brief description on how this may allow live...
KOALA is a versatile diffractometer for neutron single-crystal diffraction studies on a wide range of applications in chemistry, materials science and physics. Of the many user experiments published from KOALA data, we present two case studies related to materials science and physics.
The S=½ helical-honeycomb antiferromagnet α-Cu2V2O7 shows a broad peak in its magnetic susceptibility ∼50 K...
Densely surface-grafted polymers have attracted considerable attention due to the desirable interfacial properties that stem from both their conformation and anchored liquid-like state. To create these surfaces with desirable thicknesses and grafting densities a grafting-from approach, wherein polymers are grown from surface-attached initiators, must be used to assemble the layer. The most...
Magnonics is a new and emerging field of nanoscale science and technology. The goal of being able to produce magnonic devices is driven by the increasing needs of efficiency and speed of the technological devices our society thrives on. With the increase of energy consumption in the continuously advancing modern age, there needs to be ways in which energy is able to be produced either more...
There is a need for the development of hydrogel substrates with tuneable dissipation properties for various applications such as orthopedic load-bearing applications and scaffolds for cell culture. Tuning of stiffness and toughness by using double network gels consisting of two polymer networks has been explored for such applications. However, the mechanical properties of such hydrogels are...
We report the observation of a topological skyrmion energy barrier through a hysteresis of the skyrmion lattice in the prototypical helimagnet MnSi. Measurements of the energy barrier were made using small-angle neutron scattering and a bespoke DC field coil to allow for high-precision hysteresis loops. Data has been analyzed using an adapted Preisach model to quantify the...
The SPATZ neutron reflectometer was originally the V18 BioRef reflectometer at the BER-II Research Reactor (Berlin, Germany) [1, 2], and was transferred from HZB to ANSTO ownership during October 2016 to February 2017. The reflectometer was re-installed at ANSTO’s 20 MW OPAL Research Reactor in the Neutron Guide Hall on the end position of the newly installed CG2B cold-neutron guide. The hot...
Potential applications for gas hydrates include gas purification, water desalination, and CO2 capture that is possibly combined with methane extraction. All of these rely on the high selectivity of the guest gas molecules in hydrates. It has been shown, that the addition of TBAB (i.e. Tetra-n-butyl ammonium bromide) softens the thermodynamic conditions of gas hydrate formation without...
Unconventional hydrocarbon resources have been of large interest in recent years, hence, there are greater needs for more accurate estimations of gas reserve in the reservoirs. Although researchers use the SANS technique to investigate open and closed porosity in rocks routinely, the effects of nanopore condensation is not well understood. This study investigates the behavior of deuterated...
Multilayers of doped Silicon are the heart of the diodes and transistors which form the basis for virtually all modern electronics. With a rapidly impending need for more energy efficient computers, it is interesting to see what can be done with multilayers of more exotic starting materials. The superconductor sandwiches we study are thin-film multi-layers of the high temperature...
The double-crystal ultra-small-angle neutron scattering (USANS) diffractometer Kookaburra at ANSTO was made available for user experiments in 2014. Kookaburra allows the characterization of microstructures covering length scales in the range of 0.1–10 µm. Use of the first- and second-order reflections coming off a doubly curved highly oriented mosaic pyrolytic graphite pre-monochromator at a...
The extensive set of ternary intermetallic RMn2X2 compounds (R = rare earth, T = transitional metal, X = Ge or Si) have been investigated extensively in the past few decades due to their interesting range of physical properties [e.g. 1-3]. Recently, significant attention has been paid to the magnetocaloric effect (MCE) of RMn2X2 compounds for their potential application in magnetic...
Includes an overview of the A1B3Si2Sn7O16 (A=Fe, B=Fe,Mn) structural family and it's bi-layered structure, containing both a magnetically frustrated oxide layer and a non-magnetic FeSn6 cluster layer. It then covers the substitution of Fe with Ru in cluster layer and the effect this has on it's magnetic structure, analysed using...
A skyrmion is a topologically protected particle-like magnetic spin structures on the order of 10-100 nm. Recent studies have also shown that the skyrmions can be manipulated through applications such as an external electric fields and heat. This offers the potential for development for a much more stable, energy efficient and faster storage in memory devices. The magnetic skyrmions pack into...
Metal oxides of formula MSb$_2$O$_6$ have garnered widespread interest in materials science research as they prove to be promising materials as semiconductor photocatalysts and ionic conductors. [1] Many of these compounds (e.g. M = Co, Zn, Ni, Fe etc.) are known to crystallize in a tetragonal trirutile phase [2], although CuSb$_2$O$_6$ is known to exhibit a monoclinic distortion. [3] We are...
Three-dimensional (3D) in vitro cell culture in natural hydrogels has shown promising results in tissue engineering and biophysics as it mimics the native extracellular matrix [1]. However, compared to biosynthetic materials, the often uncontrollable and unstable structural and mechanical properties of natural hydrogels have hindered their wide use. Fibrin is a natural fibrous material that...
Chemical vapour transport (CVT) reactions has allowed for the growth of many inorganic single crystals which would be difficult or completely impossible to grow using alternative methods like flux related methods or from congruent melt. Most CVT reactions are done in evacuated and sealed quartz tubes where the internal pressure is typically in the range from 1 to 1^10-3¬ bar where diffusion is...
