Welcome to RMC 8( +1) conference after the long time in Budapest ...
Te-rich amorphous Ge-Sb-Te alloys were investigated by diffraction techniques and EXAFS. Structural models were obtained by fitting all datasets (5 for each sample) simultaneously. The results showed that the alloys are chemically ordered (number of heteronuclear bonds maximized) and obey the 8-N rule. An overview of literature data shows a strong correlation between the glass transition...
Modern extended X-ray absorption fine structure (EXAFS) analysis is based on multiple-scattering calculations. Those calculations are carried out for fixed atomic configurations and proper account of the thermal and static disorder, corresponding to well-defined pair and higher-order distribution functions, can be obtained using different methods. The application of the Reverse Monte Carlo...
Reverse Monte Carlo (RMC) simulations enable the analysis of X-ray Scattering (XS) data as well as Extended X-ray Absorption Fine Structure (EXAFS) spectra data via partial pair distribution (pPDF) functions obtained from a physical, structural model. In case of nanoparticles and scattering data this approach suffers from the termination of the pPDF’s due to the finite size of the particles....
Amorphous calcium carbonate (ACC) is an important metastable precursor for marine organism biomineralisation processes. However, the origin of the metastability of ACC is currently not well understood. Here, we use hybrid reverse Monte Carlo (HRMC) to generate atomistic models of ACC, driven by both experimental total scattering measurements [1] and interatomic potentials [2].
Using a...
Rejuvenation in glasses is defined as an excitation to a higher energy state by an external stress. Ketov et al. reported a rejuvenation effect in metallic glasses (MGs) by a temperature cycling between room and liquid N$_2$ temperatures [1]. Hufnagel reviewed such a cryogenic rejuvenation, and suggested that non-affine deformation must be caused on an atomistic length scale [2]. We carried...
Many of the useful materials that make modern life possible are crystalline. Quartz keeps our watches on time, perovskites are widely used in consumer electronics and solid oxide fuel cells may help to power the future.
The importance of local structure and disorder in crystalline materials is increasingly being recognised as a key property of many functional materials. From negative...
Molecular dynamics–reverse Monte Carlo (MD–RMC) method was applied to ZrO$_2$-doped Li$_2$O–SiO$_2$-based multi-component glass, a mother material for high-strength glass ceramics, using anomalous X-ray and neutron scattering data in order to construct a structural model of this glass. Since anomalous X-ray scattering data provide local structural information around Zr, reliable structural...
Nowadays, scientists have to work on more and more complicated materials. Description of crystal structures in terms of average structure as obtained from Bragg diffraction data analysis is no longer enough to understand material properties. Pair Distraction Function (PDF) is its natural extension and allows us to look deeper into the real (= both local and average) structure of materials....
In sodium borate glasses, boron atoms can be found in triangles (BO3) or in tetrahedral (BO4) units, which population can be easily quantified with the help of NMR spectroscopy.[1] These two speciations of boron generates the boron’s anomaly, which is a non-linear evolution of properties upon the addition of sodium oxide.[2] In addition, a large fraction of boron are involved in...
The bismuth silicate (Bi$_2$SiO$_5$) glass possesses some exceptional dielectric properties, including a high dielectric constant that is significantly larger compared to most other glasses. To gain insight into this behavior, we conducted a comprehensive analysis of the glass structure using a combination of high-energy X-ray scattering, X-ray absorption spectroscopy, and RMC modeling with a...
Complex oxides like Co3-xFexO4 spinel nanoparticles are promising heterogenous catalysts. However, the identification of quantitative structure-activity relationships of high specific surface area materials like nanoparticles is challenging. Furthermore, the distribution of cations on tetrahedrally and octahedrally coordinated sites in the spinel crystal adds...
Monosaccharides are the basic building blocks of carbohydrates, which are considered as one of the most essential biomolecules with playing principal roles in several biological processes such as molecular recognition, and structural stabilization and modification of proteins and nucleic acids that can act as cryoprotective molecules for living cells. [1]
Although monosaccharides are...
Li7P2S8I, an amorphous solid state elecrolyte reveals an increase in Li+ ion conductivity when tempered.The increase in conductivity of 0.8 mS/cm (room temperature) up to 4.6 mS/cm is shown with impedance spectroscopy [1]. The tempering temperature (180°C) is 10°C lower than the melting temperature.
Despite not overcoming the melting temperature, the x-ray diffraction pattern reveals a...
The Swedish Materials Science beamline (SMS) located at the PETRA III synchrotron storage ring (DESY Hamburg, DE) is dedicated to materials research using high-energy X-rays. The beamline consists of an inline branch (P21.2) and a side branch (P21.1), which are operated in parallel and are optimized for a combination of techniques and broad band diffraction, respectively. The inline branch...
The angular resolution in the case of angular dispersive X-ray (XRD) diffraction in transmission geometry is significantly influenced by parameters such as the size (cross-section) and divergence of the photon beam, its degree of monochromaticity, the dimensions, geometry of the sample, and the arrangement of the experiment. This work focuses on characterizing the angular resolution of the...
Polymer electrolyte fuel cells (PEFCs) consist of a gas diffusion layer (GDL) and an electrode on each side, and a polymer electrolyte membrane (MEA) between the electrodes. The main components of the MEA are catalysts, electrolyte membranes and electrodes. In this study, the local atomic structures of catalytic nanoparticles in MEA were investigated by high-energy X-ray diffraction and...
We performed reverse Monte Carlo (RMC) modeling of B2O3 glass based on high-energy X-ray total scattering data. In the B2O3 glass, the so-called boroxol rings are fromed, which are the main structural unit of the glass. Previous studies [1-3] have performed computational modeling of the three-dimensional structure of B2O3 glass, but it was difficult to achieved the expected ratio of boroxol...
In structure analysis of condensed matter by way of X-ray scattering experiments
precise treatment of background intensity is usually negligible so long as crystals
are probed, as their structure information is concentrated in sharp, highly intense
Bragg-reflexes. In less ordered systems such as liquids, glasses and amorphous
solids in general these sharp reflexes are absent and the...
Introduction
In recent years, the development of the Internet of Things (loT) has made our lives more convenient, while the power consumption of semiconductors has increased rapidly. To solve this problem, the semiconductors research has conducted to save energy through miniaturization, but new thin-film semiconductor materials are required for further expansion. Amorphous In2O3 thin films...
Cadmium cyanide exhibits the strongest persistent isotropic negative thermal expansion (NTE) effect of all known materials [1,2]. Structural studies of the material are complicated by a combination of extreme x-ray sensitivity [2], the prohibitively large neutron absorption cross-section of natural-abundance cadmium, and the presence of cyanide orientational disorder [3], which is temperature...
Compared with crystalline counterparts, metallic glasses (MGs) have some superior properties, such as high yield strength, hardness, large elastic limit, high fracture toughness and corrosion resistance, and hence are considered as promising engineering materials. Fe- and Co-based amorphous alloys have been the subject of considerable research interest and activities for the last decades due...
Toward the realization of a low-carbon society through the effective use of renewable energy, lithium-ion rechargeable batteries (LIBs) are being applied not only to portable devices but also to electric vehicles. This situation makes it to be an urgent business to develop new electrode materials with higher safety as well as higher discharge capacity than commercially available LIBs...
The advent of quantum beam sources, which can generate high-flux high-energy X-rays/neutrons, and the development of advanced instrumentations make it feasible to probe atomic arrangement in disordered materials at atomistic level with a high real space resolution. A combination of quantum-beam diffraction and data-driven structural modeling such as reverse Monte Carlo enables us to study...
The super-bandgap laser irradiation of the in situ prepared As-S chalcogenide films was found to cause drastic structural transformations and unexpected selective diffusion processes, leading to As enrichment on the nanolayer surface. Excitation energy dependent synchrotron radiation photoelectron spectroscopy showed complete reversibility of the molecular transformations and selective...
Controlling Li ion transport in glasses at atomic and molecular levels is key to realising all-solid-state batteries, a promising technology for electric vehicles. In this context, Li3PS4 glass, a promising solid electrolyte candidate, exhibits dynamic coupling between the Li+ cation mobility and the PS43− anion libration, which is commonly referred to as the paddlewheel effect1. In addition,...
Constrained big-box modelling of Prussian blue analogues
$^1$*E. A. Harbourne, $^1$J. Cattermull, $^1$N. Roth, $^2$David A. Keen, $^1$A. L. Goodwin
$^1$Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, United Kingdom
$^2$ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX
$^1$elodie.harbourne@hertford.ox.ac.uk, University of Oxford,...
The mixed ionic and electronic conduction in glasses has the potential to be used as a cathode in Li-ion batteries. The yLi2O-(100-y)TeO2 and xV2O5-(25-x)Li2O-(100-x-y)TeO2 glasses, (where x= 1,2,3,4, and 5 mol% and y= 20 and 25 mol%) were prepared by melt quenching, and their thermal, vibrational, and structural parameters are being calculated by differential scanning colorimetry, Raman...
In recent years, machine learning using liquid metal properties and theoretical models as input has led to rapid progress in the development of metallic glasses as well as many functional materials. It is therefore expected to become important in the future to use liquid structures as training data for machine learning to predict glass-forming ability. However, as metallic glasses are often...
X-ray absorption spectroscopy (XAS) is an element-selective structural technique that provides information about the local environment of a specific element. In multicomponent materials, such as complex solid solutions, medium- and high-entropy alloys, XAS enables independent probing of each element by selecting the X-ray photon energy corresponding to its absorption edge. Consequently, a...
Thorough examination of the lattice dynamics of hexagonal close-packed titanium and zirconium was conducted in this study using the extended X-ray absorption fine structure (EXAFS) spectroscopy. The analysis of Ti and Zr K-edge EXAFS spectra, employing the reverse Monte Carlo method [1], facilitated the determination of mean-squared relative displacements (MSRDs) for Ti-Ti and Zr-Zr atom...
The orientational correlation scheme introduced earlier for tetrahedral molecules [R. Rey, J. Chem. Phys., 126 (2007) 164506] is extended [L. Temleitner, J. Mol. Liq., 341 (2021) 116916.] for being able to classify orientational correlations between pairs of high symmetry molecules. While in the original algorithm a given orientation of a pair of tetrahedral molecules is characterized...
Lattice dynamics of bulk NiO was studied at seven temperatures from 10 K to 300 K using the Ni K-edge X-ray absorption spectroscopy combined with the reverse Monte Carlo simulations. Lattice dynamics calculations with empirical potential were also performed for comparison. The potential model was validated by comparing the experimental Ni K-edge extended X-ray absorption fine structure (EXAFS)...
In the area of atomic-level structure modeling, there are two well known parallel problems. The theory driven modeling usually cannot fully account for the disorder of practical system and therefore may fail to reproduce the complete picture of structure model as observed experimentally. The data driven approach tries to derive the structural model from the experimental data in a reverse...
