Analysis Of X-ray Diffraction Data Research Articles

Synthesis of Graphite-Encapsulated Ni Micro- and Nanoparticles Using Liquid-Phase Arc Discharge

In this work, the synthesis of nickel particles encapsulated in a few-layer graphene shell was carried out using the method of electric arc discharge in the liquid phase, in various media: deionized water, alcohol, and toluene. Nickel and graphite were used as electrodes. The study was carried out to analyze how various liquids, acting as a cooling medium and a source of carbon, affect the formation of a protective shell around metal particles. Raman studies, analysis of X-ray diffraction data, and scanning electron microscopy confirmed the formation of spherical encapsulated nickel particles in all types of liquid media. It was found out that the use of toluene as a cooling medium increased the number of particles with a graphite shell and allowed obtaining micro- and nanoparticles covered with monolayer graphene. The absence of oxygen in the composition of toluene, in contrast with alcohol and especially water, prevents the oxidation of nickel particles during the synthesis. This fact, along with the initial basic hexagonal carbon structure of toluene, makes it a good medium for the formation of metal particles covered with a protecting graphite shell as a result of arc discharge in the liquid phase.

Synthesis and characterization of strontium tartrate tetrahydrate crystal using silica gel method

In the present study, strontium tartrate tetrahydrate crystals were grown using the silica gel method. Optimum growth parameters were obtained by varying molar concentration, volume of upper reactant solution, and pH of gel mixture at ambient temperature (31 °C). Large size crystal (9 × 8 × 4 mm3) of strontium tartrate tetrahydrate were obtained when the pH of the gel mixture was 4.2 and upper reactant had a molar concentration of 1.5 M and volume of 20 ml. As grown crystal was characterized using different techniques viz. Powder X-ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), Energy Dispersive Analysis of X-ray (EDAX), and UV–vis spectral analysis. Analysis of Powder X-ray diffraction data carried out in the 2θ range 10°–60° revealed that as grown crystal had an orthorhombic structure with space group P2 2 2 and unit cell parameters a = 9.8865 Å, b = 10.0448 Å, c = 9.5186 Å, α = β = γ = 90°. Various vibrational peaks of hydroxyl group (OH) at wavenumber 3170.42, 3384.44, 3536.72 cm−1, carbonyl (CO) group at 1601.88 cm−1 were observed in FTIR spectroscopy. One peculiar peak at 478.2 cm−1 where one O− and was replaced by Sr2+ was also obtained in FTIR spectroscopy suggesting formation of strontium tartrate crystal. Energy dispersive analysis of X-ray confirms the presence of expected major elements like strontium, carbon, and oxygen in the crystal. UV–vis transmission spectrum of strontium tartrate tetrahydrate crystals was recorded in the wavelength range of 190 to 1100 nm. The energy bandgap estimated from transmission data is 5.64 eV. Non-linear Optical (NLO) competence of STT crystal is observed at 532 nm. The electrical property of pelletized samples was studied by dielectric measurement in the frequency range of 20 Hz–2 MHz at room temperature. It is observed that dielectric loss is very low at higher frequency.

Sol-Gel Synthesis and Characterization of Novel Y3−xMxAl5−yVyO12 (M—Na, K) Garnet-Type Compounds

In this study, for the first time to the best of our knowledge, the new garnets Y3−xNaxAl5O12, Y3−xKxAl5O12, Y3Al5−yVyO12, and Y3−xNaxAl5−yVyO12 with various stoichiometric compositions were successfully synthesized by the aqueous sol-gel method. All obtained samples were characterized by X-ray diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). It was determined from the XRD results that the formation of monophasic Y3−xNaxAl5O12, Y3−xKxAl5O12, Y3Al5−yVyO12, and Y3−xNaxAl5−yVyO12 garnets is possible only at limited doping levels. The highest substitutional level of doped metal was observed for the YAG doped with sodium (x = 1), and the lowest substitutional level was observed for the YAG doped with vanadium (y = 0.05). Furthermore, the obtained FTIR spectroscopy results were in good agreement with the XRD analysis data, i.e., they confirmed that the YAG is the main crystalline phase in the end products. The SEM was used to study the morphology of the garnets, and the results obtained showed that all synthesized samples were composed of nano-sized agglomerated crystallites.

Enhanced Oxide Ion Conductivity by Ta Doping of Ba3Nb1-xTaxMoO8.5.

Significant oxide ion conductivity has previously been reported for the Ba3M'M″O8.5 family (M' = Nb5+, V5+; M″ = Mo6+, W6+) of cation-deficient hexagonal perovskite derivatives. These systems exhibit considerable structural disorder and competitive occupation of two distinct oxygen positions (O3 site and O2 site), enabling two-dimensional (2D) ionic conductivity within the ab plane of the structure; higher occupation of the tetrahedral O3 site vs the octahedral O2 site is known to be a major factor that promotes oxide ion conductivity. Previous chemical doping studies have shown that substitution of small amounts of the M' or M″ ions can result in significant changes to both the structure and ionic conductivity. Here, we report on the electrical and structural properties of the Ba3Nb1-xTaxMoO8.5 series (x = 0.00, 0.025, 0.050, 0.100). AC impedance measurements show that substitution of Nb5+ with Ta5+ leads to a significant increase in low-temperature (<500 °C) conductivity for x = 0.1. Analysis of neutron and X-ray diffraction (XRD) data confirms that there is a decrease in the M1O4/M1O6 ratio upon increasing x from 0 to 0.1 in Ba3Nb1-xTaxMoO8.5, which would usually coincide with a lowering in the conductivity. However, neutron diffraction results show that Ta doping causes an increase in the oxide ion conductivity as a result of longer M1-O3 bonds and increased polyhedral distortion.

Convolutional neural network analysis of x-ray diffraction data: strain profile retrieval in ion beam modified materials

This work describes a proof of concept demonstrating that convolutional neural networks (CNNs) can be used to invert x-ray diffraction (XRD) data, so as to, for instance, retrieve depth-resolved strain profiles. The determination of strain distributions in disordered materials is critical in several technological domains, such as the semiconductor industry for instance. Using numerically generated data, a dedicated CNN has been developed, optimized, and trained, with the ultimate objective of inferring spatial strain profiles on the sole basis of XRD data, without the need of a priori knowledge or human intervention. With the example ZrO2 single crystals, in which atomic disorder and strain are introduced by means of ion irradiation, we investigate the physical parameters of the disordered material that condition the performances of the CNN. Simple descriptors of the strain distribution, such as the maximum strain and the strained depth, are predicted with accuracies of 94% and 91%, respectively. The exact shape of the strain distribution is predicted with a 82% accuracy, and 76% for strain levels <2% where the amount of meaningful information in the XRD data is significantly decreased. The robustness of the CNN against the number of predicted parameters and the size of the training dataset, as well as the uniqueness of the solution in some challenging cases, are critically discussed. Finally, the potential of the CNN has been tested on real, experimental, data. Interestingly, while the CNN has not been trained to operate on experimental data, it still shows promising performances with predictions achieved in a few seconds and corresponding root-mean-square errors in the 0.12–0.17 range for a fully automated approach, vs. a 0.06–0.12 range for a classical, human-based, approach that, in turn, requires several tens of minutes to optimize the solution. While the overall accuracy of the CNN has to be improved, these results pave the way for a fully automated XRD data analysis.

The Effects of Thermal Treatment on the Properties and Performance of Hot Extruded Zn-Based Bioresorbable Alloy for Vascular Stenting Applications.

A new series of zinc alloys is in development for bioresorbable stent implantation to alleviate the current materials' long-term complications. Characterization and optimization of the microstructure and corresponding mechanical properties during manufacturing stages will help researchers meet the required values. In this study, the effect of hot extrusion on the Zn-Ag-Mn-Cu-Zr-Ti alloy is characterized. Additionally, thermal treatments at 390 °C for 15, 25, 40, 60, and 120 min were performed to evaluate the effect of intermetallic phase fractions on the corrosion resistance and mechanical strength. Quantitative analysis of X-ray diffraction data demonstrates that the fractions of the MnZn13, ZrZn22, and Zn0.75Ag0.15Mn0.10 intermetallic phases decrease as the thermal treatment time increases. Corrosion tests reveal a reduction in the corrosion rate of the extruded alloy after thermal treatment. The results of uniaxial compression tests and tensile tests show lower strength and higher ductility in all heat-treated conditions compared with the as-extruded condition.

Oxygen distribution in the structure of YBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-delta-=/SUB=- thin films after vacuum exposure at 300 K

We have found out that vacuum exposure of YBa2Cu3O7-delta thin epitaxial films at 300 K for 24 hours decreases oxygen content and induces changes in their crystal structure depending on the films synthesis conditions. YBa2Cu3O7-delta films on SrTiO3 (100) substrates were synthesized by pulsed laser deposition. The crystal structure was studied using XRD technique. Additional maxima of diffraction peak (005) before and after vacuum exposure indicate the presence of regions with different oxygen content; and the change in the shape of the rocking curves indicate a change in the crystallites orientation. After vacuum exposure, the oxygen deficiency delta in the films increased from ~0.01 to ~0.6 for films with a crystallites size of 2-10 nm and from ~0.25-0.35 to ~0.6 for crystallites size of 500-1000 nm. The appearance of a residual resistance after the superconducting transition in the dependence R(T) may be explained by the fact that oxygen loss mainly in the boundary regions of the crystallites takes place, so that their boundaries become dielectric, while the crystallites themselves remain superconductive. Based on the data of X-ray diffraction analysis, as well as resistive measurements, we have come to the conclusion about oxygen loss through grain boundaries in films with nanocrystallites of 2-10 nm in size, and also through structural defects in films with larger crystallites. Keywords: pulsed laser deposition, surface relief, transport characteristics of films, film evolution, SrTiO3.

Кинетика формирования сверхструктуры L10 в сплаве Cu–56Au (ат. %): резистометрическое исследование

Due to the improved strength properties compared to the equiatomic Cu–50 at. % Au alloy, non-stoichiometric Cu–56 at. % Au alloy can be used both in dentistry and as a corrosion-resistant conductor of weak electrical signals in tool engineering. The work studies the kinetics of the disorder→order phase transformation in the Cu–56Au alloy, during which the disordered fcc lattice (A1-phase) is rearranged into an atomically ordered one with the L10 superstructure. The initial disordered state of the alloy was obtained in two ways: applying plastic deformation by 90 % or quenching at a temperature of above 600 °C (i. e., from the region of the A1-phase existence). To form the L10 superstructure, annealing was carried out at temperatures of 200, 225, and 250 °C. The annealing duration ranged from 1 h to 2 months. Resistometry was chosen as the main technique to study the kinetics of the disorder→order transformation. The temperature dependences of the electrical resistivity of the alloy in various structural states are obtained. The authors constructed the graphs of the electrical resistance dependence on the annealing time logarithm, based on which, the rate of the new phase formation was estimated. To evaluate the structural state of the alloy at various transformation stages, the authors used X-ray diffraction analysis (XRD). The crystal structure rearrangement during the transformation is shown by the example of splitting the initial cubic A1-phase peak (200) into two tetragonal ordered L10 phase peaks – (200) and (002). Based on the resistometry and X-ray diffraction analysis data, the authors carried out a quantitative assessment of the rate of the disorder→order phase transformation in the alloy under the study. It is established that the values of the converted volume fraction (resistometry) and the long-range order degree (X-ray diffraction analysis) are close. The study shows that in the temperature range of 200–250 °C, the rate of atomic ordering according to the L10 type in the nonstoichiometric alloy Cu–56 at. % Au is maximum at 250 °C. It is identified that the disorder→order transformation in the initially quenched specimens of the investigated alloy proceeds approximately an order of magnitude faster than in preliminarily deformed specimens.

Реакции пентафенил- и пента(пара-толил)сурьмы с ферроцендикарбоновой кислотой

In reactions of pentaphenyl- and penta(para-tolyl)antimony with ferrocene dicarboxylic acid (molar ratios 1:1 and 2:1) in toluene (20 С, 24 h), hydrogen in one or two carboxylate groups is replaced with formation of tetraarylantimony ferrocene carboxylates HOOС5H4FeС5H4C(O)OSbPh4 (1), HOOС5H4FeС5H4C(O)OSbTol4 (2), Ph4SbC(O)OC5H4FeС5H4C(O)OSbPh4 (3) and p-Tol4SbC(O)OC5H4FeС5H4C(O)OSbTol4 (4), yielding up to 83 %. Compounds 1–4 have been identified by elemental analysis, IR spectroscopy, and X-ray diffraction analysis for 4. X-ray diffraction analysis of complex 4 has been performed on a D8 Quest Bruker automatic four-circle diffractometer (Mo Kα radiation, λ = 0.71073 Å, graphite monochromator ) at 293 K. Crystallographic characteristics of compound 4: monoclinic system, space group P21/c, a = 17.227(17), b = 11.064(9), c = 30.59(3) Å, β = 100.00(4) deg., V = 5742(9) Å3, Z = 4, calc = 1.440 g/cm3, 2 6.02-49.08 deg., total reflections 124343, independent reflections 9436, number of refined parameters 684, Rint = 0.1051, GOOF 1.094, R1 = 0.0536, wR2 = 0.1309, residual electron density (max/min) 0.88/1.21 e/Å3. According to the X-ray diffraction analysis data, in crystal 4 coordination of the antimony atoms is distorted octahedral due to the fact that the carboxylate ligand is a bidentate chelating ligand. The diagonal angles in the two octahedra are 146.4(2), 154.0(3), 171.0(2) and 147.4(2), 154.8(2), 166.9(2). The SbO distances are 2.296(5), 2.502(5) Å and 2.289(5), 2.453(5) Å, the SbC bonds are significantly different (2.146(7)2.166(7) and 2.123(6)2.165(7) Å). The structural organization of the crystal is mainly due to the interactions of the СН•••-type.

Синтез и кристаллическая структура бис(2-метилкарборанил-карбоксилата) трис(3-фторфенил)сурьмы

Oxidation of tris(3-fluorophenyl)antimony with hydrogen hydroperoxide in the presence of 2-methylcarboranylcarboxylic acid leads to the formation of tris(3-fluorophenyl)antimony bis(2-methylcarboranylcarboxylate) (1), the structural features of which have been established by X-ray diffraction analysis. According to X-ray diffraction analysis performed at 293 K on an automatic four-circle diffractometer D8 Quest Bruker (two-coordinate CCD detector, Mo Kα-radiation, λ = 0.71073 Å, graphite monochromator), the crystals are characterized by: C26H38B20F3O4Sb, M 809.52; monoclinic system, space group С2/c; cell parameters: a = 19.050(13), b = 14.441(9), c = 14.568(9) Å;  = 90, β = 98.51(2),  = 90; V = 3964(4) Å3; Z = 4; crystal size 0.8 × 0.55 × 0.29 mm; index ranges –25 ≤ h ≤ 25, –18 ≤ k ≤ 18, –18 ≤ l ≤ 19; total reflections 37401; independent reflections 4709; Rint 0.0545; GOOF 1.108; R1 = 0.0578, wR2 = 0.1482; residual electron density –0.59/1.09 e/Å3. According to X-ray diffraction analysis data, in the molecules of compound 1, the antimony atoms have a distorted trigonal-bipyramidal coordination with the oxygen atoms of the carboxylate ligands in the axial positions. The Sb–C bonds (2.104(4)–2.114(8) Å) are shorter than the Sb–O distances (2.113(3) Å), the OSbО axial angle is 178.48(15)°, the CSbC angles are 109.7(2)°, 118.4(2)°, 131.8(3)°, while a significant increase in one of the angles is associated with the cis-conformation of the carboxylate ligands relative to the equatorial plane. The conformation of aryl ligands with respect to the equatorial plane [C3] is propeller. Structure 1 contains intramolecular Sb•••O=С contacts between the antimony and oxygen atoms of the carbonyl groups of the carboxylate ligands, which are 3.089(3) Å. The formation of a spatial network in the crystal of compound 1 is due to the presence of weak hydrogen bonds with the participation of boron atoms of carboxylate ligands and fluorine of aryl ligands: B•••H (3.19 Å) and F•••B (3.45 Å). Complete tables of atomic coordinates, bond lengths, and bond angles are deposited at the Cambridge Structural Data Center (no. 2178731; deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/ cif).

Antisite disorder and Berry curvature driven anomalous Hall effect in the spin gapless semiconducting Mn2CoAl Heusler compound

Spin gapless semiconductors exhibit a finite band gap for one spin channel and a closed gap for another spin channel, and they have emerged as a new state of magnetic materials with a great potential for spintronic applications. The first experimental evidence for spin gapless semiconducting behavior was observed in an inverse Heusler compound ${\mathrm{Mn}}_{2}\mathrm{CoAl}$. Here, we report a detailed investigation of the crystal structure and anomalous Hall effect in ${\mathrm{Mn}}_{2}\mathrm{CoAl}$ using experimental and theoretical studies. The analysis of the high-resolution synchrotron x-ray diffraction data shows antisite disorder between Mn and Al atoms within the inverse Heusler structure. The temperature-dependent resistivity shows semiconducting behavior and follows Mooij's criteria for disordered metal. The scaling behavior of the anomalous Hall resistivity suggests that the anomalous Hall effect in ${\mathrm{Mn}}_{2}\mathrm{CoAl}$ is primarily governed by an intrinsic mechanism due to the Berry curvature in momentum space. The experimental intrinsic anomalous Hall conductivity (AHC) is found to be $\ensuremath{\sim}35$ S/cm, which is considerably larger than the theoretically predicted value for ordered ${\mathrm{Mn}}_{2}\mathrm{CoAl}$. Our first-principles calculations conclude that the antisite disorder between Mn and Al atoms enhances the Berry curvature and hence the value of intrinsic AHC, which is in very good agreement with the experiment.

Bis-(2-difluoroamino-2,2-dinitroethyl)nitramine – Energetic oxidizer and high explosive

• Bis-(2-difluoramino-2,2-dinitroethyl)nitramine ( 1 ) is synthesized. • 1 has a very high density of 2.032 g cm −3 at 298 K. • Thermochemical and kinetic data is reported. • Specific impulse is improved over standard AP-based formulations. • 1 reaches the detonation performance level of landmark CL-20. There is an urgent demand for novel energetic materials with improved performance to serve as oxygen suppliers (oxidizers) and high-energy additives. Synthesis and characterization of compound that combines both of the above roles, bis-(2-difluoroamino-2,2-dinitroethyl)nitramine ( 1 ), is reported. 1 was synthesized by difluoroamination of bis(2,2-dinitroethyl)nitramine in good yield. The analysis of X-ray diffraction data shows that NF 2 -groups has a significant contribution into a very high density of 1 , 2.032 g cm −3 at 298 K. The positive oxygen balance (+8%) makes it an attractive oxidizer, the rocket specific impulse is improved to 277 s vs 265 s for standard ammonium perchlorate-based formulation. Furthermore, the detonation performance of 1 reaches the level of most powerful explosive, CL-20. As a way to tune the melt-casting temperature and decrease the high friction sensitivity of 1 , its eutectics with trinitrotoluene were proposed.

Stabilised mechanical properties in Ni-based Hastelloy C276 alloy by additive manufacturing under different heat inputs incorporated with active interlayer temperature control

In this study, a Ni-based Hastelloy C276 alloy was prepared using cold metal transfer (CMT)-based directed energy deposition (DED) under different heat inputs with a zig-zag deposition path, integrated with active cooling and interlayer temperature control. Analogous mechanical properties were obtained for the fabricated alloys under different heat inputs (276, 368 and 553 J/mm) through effective interlayer temperature control. Such a broad processing window facilitates the large-scale industrial manufacturing and application of Hastelloy C276 by DED. Nevertheless, the lower heat input appears to slightly refine the microstructure and decrease the mechanical anisotropy of manufactured alloys, which is ascribed to combined effects of the manipulated bulk texture, refined dendrite arm spacing and reduced chemical segregation under lower heat input. Despite the variations of geometrically necessary dislocation (GND) densities with heat inputs, no significant change was observed in the average total dislocation density (TDD) in the microstructure of all samples as suggested by the peak profile analysis of Synchrotron X-ray diffraction data, which is advantageous for lowering the solidification cracking susceptibility. Moreover, all as-fabricated alloys present a typical strong fibre-type (200) crystallographic bulk texture measured by neutron diffraction, while such texture was relatively weaker in the lowest heat input condition. This work provides a reliable approach for stable additive manufacturing of Hastelloy C276 alloy, and innovatively presents rationales of stabilised properties based on the obtained insights into microstructure and bulk texture developments in a wide observation range by various techniques.

Zr3Mn3Sn4Ga: a new hexagonal Ti6Sn5-type quaternary intermetallic

The discovery of a new quaternary intermetallic compound of composition Zr3Mn3Sn4Ga during a survey of the Zr–Mn–Sn–Ga phase diagram is reported. Single-crystal X-ray diffraction reveals that the new compound crystallizes in a hexagonal lattice (space group P63/mmc, No. 194). The analysis of single-crystal X-ray diffraction data indicates that the atomic arrangement is an ordered variant of the high-temperature hexagonal Ti6Sn5 crystal structure. From a simple geometry point of view, the unit cell consists of GaZr3 octahedra chains and Mn chains growing along the sixfold symmetry axis c. The Mn chains are stacked within the ab basal plane in a kagome geometry, with large interatomic distances. The possible slight levels of Sn/Ga and Zr/Mn mixed occupancy based on additional results of electron probe microanalysis and single-crystal neutron diffraction are discussed. It is noteworthy that this compound is the first quaternary intermetallic discovered in this structure and the first Ti6Sn5 derivative bearing a magnetic metal, namely Mn, in the 6g position, which may give rise to interesting physical properties.

Structure and magnetic properties of (Mg1/6Zn1/6Mn1/6Co1/6Ni1/6Fe1/6)3O4 nanocrystalline high-entropy oxide synthesized using a sol-gel auto combustion approach

A sol–gel auto-combustion method is used in this study to synthesize a new class of single-phase high-entropy oxide (HEO) (Mg1/6Zn1/6Mn1/6Co1/6Ni1/6Fe1/6)3O4. The as-synthesized compound exhibits a single-phase spinel structure with an 8.3224 Å lattice parameter and an average crystallite size of 10 nm as determined by X-ray diffraction (XRD) data analysis. Raman and Fourier transform infrared results are in agreement with the XRD results. A scanning electron microscopy-based energy dispersed spectroscopy study suggests the formation of a porous structured morphology with a uniform elemental distribution. In addition, high-resolution transmission electron microscopy and surface analyses further confirm the formation of a pure spinel structure with a particle size of 12–20 nm and a mesoporous character with a pore size of 4.55 nm. X-ray photoelectron spectroscopy indicates mixed-valence states of elements (Mn, Fe, Co, and Ni) and their occupations over tetrahedral and octahedral sites. The temperature-dependent magnetization exhibited a bifurcation between zero-field-cooled and field-cooled magnetizations. From the M−H curves, the magnetization decreased monotonically with the increase in temperature (M is 22 emu/g at 2 K and 7.2 emu/g at 300 K). The coercivity decreased by approximately-one order of magnitude (HC = 1700 Oe at 2 K and HC = 200 Oe at 370 K). Finally, a comprehensive magnetic characterization of the as-synthesized HEO indicates their ferrimagnetic nature. The novel physical properties of the as-synthesized HEO could be useful in various potential applications.

Crystal structure, electric and microwave dielectric properties of La2Mg(Mg1/3Sb2/3)O6 novel double-perovskite with non-stoichiometric 1:1 cationic ordering

In this contribution, the novel double-perovskite La2Mg(Mg1/3Sb2/3)O6 has been successfully prepared by solid-state reaction method, and its structure has been determined for the first time by a combination of X-ray and neutron powder diffraction data analysis. The novel material exhibits a thermal expansion of ∼9.1 ppm/°C and a large optical band gap (4.23 eV). The complex impedance data analysis indicates that La2Mg(Mg1/3Sb2/3)O6 features a Debye-like behaviour, with a bulk conductivity, σb, varying between 10-7-10-4 S ‧cm-1 within 500–900 °C temperature range, and activation energy (Ea) of ∼ 1.36 eV. In addition, the microwave dielectric properties of La2Mg(Mg1/3Sb2/3)O6 sintered at 1625 °C display optimized quality factor (Q×f) of ∼ 28,700 GHz (f = 9.65 GHz), a dielectric constant (εr) of ∼ 20.2 and temperature coefficient of the resonant frequency (τf) of ∼ − 89 ppm/°C. This work widen the reduced number of A3+B2/32+B1/35+O3 compounds explored so far.

Self-Assembled glycerol monooleate demixes miscible liquids through selective hydrogen bonding to water

Water is miscible with dimethylsulfoxide (DMSO), with which it interacts through hydrogen bonds (H-bonds). Glycerol monooleate (GMO, 53 g/L) demixes water and DMSO, yielding kinetically stable DMSO in water emulsions with up to ≈75 % DMSO (relative to water, v/v), as demonstrated by Fourier Transform Infrared (FTIR) spectromicroscopy, ultra small angle X-ray scattering (USAXS) and light scattering experiments, and optical microscopy. With > 75 % DMSO (relative to water) emulsions reverse and DMSO becomes the continuous phase (as shown by electrical conductivity measurements). The size of emulsified droplets decreases with increasing DMSO ratios (relative to water), as demonstrated by USAXS. Synchrotron X-ray Diffraction (XRD) measurements conducted in the small (SAXS) and wide angle (WAXS) regions show that the DMSO:water ratio affects GMO self-assembly. GMO (53 g/L) self-assembles into cubic crystal mesophases with 40 % DMSO (relative to water) and into disordered lamellar phases with 50 % DMSO. At even higher DMSO percentages, GMO self-assembles into reverse micelles, which contain water and are surrounded by DMSO (as shown by analyzing XRD data with the Steubner and Strey model). Although GMO mainly partitions in the DMSO rich phase, attenuated total reflectance (ATR)-FTIR measurements show that GMO interacts with water through H-bonds. Importantly, it increases the proportion of single H-bond donors (SD, which structure water the most) relative to double donors (DD, which structure water less). H-bonding between the hydrophilic head of GMO and initiates separation between DMSO and water, which would be H-bonded to one another in the absence of GMO. While this study focuses on DMSO, GMO also emulsifies water and tetrahydrofuran (THF), dimethylformamide (DMF) and dioxane. Our findings redefine which solvents can be emulsified with water, and have potential implications for water treatment.

Domain Auto Finder (DAFi) program: the analysis of single-crystal X-ray diffraction data from polycrystalline samples.

This paper presents the Domain Auto Finder (DAFi) program and its application to the analysis of single-crystal X-ray diffraction (SC-XRD) data from multiphase mixtures of microcrystalline solids and powders. Superposition of numerous reflections originating from a large number of single-crystal domains of the same and/or different (especially unknown) phases usually precludes the sorting of reflections coming from individual domains, making their automatic indexing impossible. The DAFi algorithm is designed to quickly find subsets of reflections from individual domains in a whole set of SC-XRD data. Further indexing of all found subsets can be easily performed using widely accessible crystallographic packages. As the algorithm neither requires a priori crystallographic information nor is limited by the number of phases or individual domains, DAFi is powerful software to be used for studies of multiphase polycrystalline and microcrystalline (powder) materials. The algorithm is validated by testing on X-ray diffraction data sets obtained from real samples: a multi-mineral basalt rock at ambient conditions and products of the chemical reaction of yttrium and nitro-gen in a laser-heated diamond anvil cell at 50 GPa. The high performance of the DAFi algorithm means it can be used for processing SC-XRD data online during experiments at synchrotron facilities.

Two-step combustion synthesis of single-phase mesoporous ScFeO3 with bixbyite structure and magnetically soft behavior

In this paper, we consider the possibility of obtaining cubic bixbyite-type scandium ferrite in the form of phase-pure nanopowders. The samples were obtained by solution combustion method with either lack or excess of fuel and represented an X-ray amorphous phase according to the X-ray diffraction (XRD) results. To obtain cubic scandium ferrite, the samples were subjected to heat treatment at 700 °C, determined using DTA/TGA. The XRD data analysis confirmed the formation of cubic scandium ferrite with an average crystallite size of ∼20 nm for the sample obtained with a lack of fuel and 13 nm with an excess of fuel. According to the low-temperature nitrogen adsorption-desorption technique, the specific surface of the mesoporous samples decreased after annealing from 39.7 m2/g to 20.5 m2/g for the sample obtained with a lack of fuel and from 82.7 m2/g to 34 m2/g for the sample obtained with excess fuel. Scanning electronic microscopy (SEM) results demonstrated the foam-like morphology of nanopowders and no significant changes in their microstructure after heat treatment. The magnetic properties of powders that have undergone heat treatment have been studied. Narrow M-H hysteresis loops and low values of the coercive force indicate ferromagnetic behavior of the synthesized nanoparticles, which is supported by low values of the coercive force (Hc = 345 Oe and 769 Oe), remanent magnetization (Mr = 0.65 emu/g and 0.26 emu /g) and saturation magnetization (Ms = 1.69 emu/g and 0.26 emu/g) for lack and excess of fuel, respectively. The obtained materials are classified as magnetically soft and can potentially be used in the creation of transformers, magnetic screens, magnetic memory systems, radio engineering, and computer technology.

A study on the electrical properties of flux grown 0.91PZN-0.09PT single crystals for high-performance piezoelectric and pyroelectric device applications

In the present work, large-size piezoelectric single crystals of 0.91[Pb(Zn1/3Nb2/3)O3]-0.09PbTiO3 (PZN-9PT) have been grown by high-temperature flux method. Rietveld refinement analysis of X-ray diffraction data demonstrates the existence of monoclinic [Cm and Pm] phases, further supported by electron diffraction studies. PZN-9PT single crystal shows broad and diffused dielectric response peaks at 354 K and 443 K with noticeable frequency dispersion identified from temperature-dependent dielectric measurements. The 001 oriented PZN-9PT elements sliced from the grown single crystals display a remnant polarisation (Pr) of 30 µC/cm2, saturation polarization (Ps) of 33 µC/cm2, and an enhanced piezoelectric strain of 0.3 %. In addition, the piezoelectric coefficients d33, d31 and electric field-induced strain d33∗ measured by the direct method is 2100 pC/N, 1650 pC/N and 2500 pm/V, respectively. The mechanism behind the enhanced piezoelectric properties of PZN-9PT is explained with reference to the stabilization of the monoclinic phase and polarization rotation mechanisms. Further, the pyroelectric coefficient, p measured to be 11.31 × 10−4 C/m2 K at room temperature and 51.22 × 10−4 C/m2 K at the ferroelectric to the paraelectric phase transition temperature. The enhanced piezoelectric and pyroelectric properties of PZN-9PT make them suitable for high-performance piezoelectric transducers, actuators at ambient temperature and pyroelectric sensors at elevated temperature, respectively.