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Although XLPE cables are widely used in power transmission and distribution systems, their insulating properties are susceptible to degradation due to thermal aging. In order to clarify the influence law of the thermal aging process on the structural and dielectric properties of XLPE cables, this paper investigates the thermal aging characteristics of XLPE cables by using polarization and depolarization current measurement. Results show that when the XLPE cable is aged at 140 °C, the crystallinity of the insulation layer appears to increase and then decrease. With the increase in aging time, micron-sized microvoids appear on the surface of the XLPE. At the same time, the DC conductivity and 0.1 Hz dielectric loss factor of the insulating layer increase with the aging time. The average DC conductivity increased from 2.26 × 10−16 S/m for new cables to 4.47 × 10−16 S/m after aging for 432 h, while the dielectric loss increased from 0.11% to 0.42%. The polarization characteristics of thermal-aged cables were further analyzed using the extended Debye model. Results indicate that the time constant of the third branch of the model increased significantly with increasing aging time. A correspondence between this parameter and the thermal aging time of the cable was established. Thermal aging can damage the crystalline structure of XLPE, so that the number of interfaces between the crystalline and amorphous regions of the material increases, resulting in structural damages and a decline in the dielectric properties of the cable insulation. [ABSTRACT FROM AUTHOR]

Nanofibrillated cellulose (NFC) consists of ultrafine cellulose structures in which the fibrils can have widths in the range from about 5 to 100 nm. NFC has been studied and developed in the paper industry, using bleached pulp from wood as the raw material. One of the issues in the application of NFC is their heat resistance to thermal degradation. The production process of NFC results in a decrease in their pyrolysis temperature during the nanofibrillation of bleached pulp; however, the details behind the reason and mechanisms are still unclear. In this study, NFC was prepared from bleached hardwood and softwood pulp by mechanical nanofibrillation using a grinder, and the pyrolysis behavior was investigated. For both bleached pulps, a decrease in the pyrolysis temperature was observed after nanofibrillation. The results suggest that the decrease in the pyrolysis temperature from nanofibrillation is not due to damage of the crystalline cellulose by nano fibrillation, but the damage of the hemicellulose components in the surface of the cellulose microfibrils or the interface between the crystalline cellulose and hemicellulose. If the hemicellulose on the surface of crystalline cellulose could be removed from the NFC, then the decrease in the pyrolysis temperature could be suppressed. [ABSTRACT FROM AUTHOR]

Spherulite-related space–charge electret properties of polypropylene (PP) have been widely discussed in the past decades. In the present paper, a less-common crystalline structure in PP—transcrystalline PP—is studied regarding its electret behavior in comparison with the typical spherulitic morphology. Polarized light microscopy and differential scanning calorimetry were employed to characterize the crystallite types and crystallinities of transcrystalline and spherulitic PP. Their electret functionality is investigated by means of thermally stimulated discharge experiments, where the cross-over phenomenon is observed on transcrystalline PP films, whereas surface-potential saturation and undercharging on the surface occur on the spherulitic samples. Besides, an asymmetrical behavior of positive and negative surface-charge stabilities is found on PP with spherulites, the negatively charged spherulitic surfaces show a better charge stability. It is shown that PP electrets are very sensitive to changes in the microscopic crystalline structures and their interfaces as well as in the molecular conformations controlled through adjustments of the respective processing steps. In addition, surface and bulk nanocomposites of PP or low-density polyethylene with inorganic particles are included in the comparison. In view of recent developments in the areas of PP-based electret-fiber filters and cellular-foam ferroelectrets, the observed changes in the charge-storage properties may have particular relevance, as the required film, fiber, or foam processing might significantly modify crystalline morphologies and nano-scale interfaces in PP electrets. Limitations in the charge-storage capabilities of interface structures may also be of interest in the context of high-voltage electrical-insulation materials where reduced space–charge accumulation and slightly increased charge transport can be advantageous. [ABSTRACT FROM AUTHOR]

We calculate the degree to which the final structure of the local groundstate in a liquid is a function of the strength of a perturbing potential applied during energy minimization. This structural susceptibility is shown to correlate well with the observed tendency of the liquid adjacent to a crystal interface to exhibit a crystalline groundstate, a feature that has been strongly linked to the observation of ultra-fast crystal growth in pure metals and ionic melts. It is shown that the structural susceptibility increases dramatically as the interaction potential between atoms is softened. [ABSTRACT FROM AUTHOR]

An analysis is presented of the new types of defects that can appear in crystalline structures where the positions of the atoms and the unit cell belong to the same -module, i.e. are irrational projections of an N > 3-dimensional ( N-D) lattice Λ as in the case of quasicrystals. Beyond coherent irrationally oriented twins already discussed in a previous paper [Quiquandon et al. (2016). Acta Cryst. A 72, 55-61], new two-dimensional translational defects are expected, the translation vectors of which, being projections of nodes of Λ, have irrational coordinates with respect to the unit-cell reference frame. Partial dislocations, called here module dislocations, are the linear defects bounding these translation faults. A specific case arises when the Burgers vector B is the projection of a non-zero vector of Λ that is perpendicular to the physical space. This new kind of dislocation is called a scalar dislocation since, because its Burgers vector in physical space is zero, it generates no displacement field and has no interaction with external stress fields and other dislocations. [ABSTRACT FROM AUTHOR]

OER (oxygen evolution reaction) is a critical reaction in several storage and conversion systems for renewable and clean electrochemical energies, including solar fuel devices, metal–air batteries, as well as regenerative fuel and water splitting cells. Regarding the shortcomings of OER, apart from the sluggish kinetics and high reaction overpotential, the reaction rate and overpotential are difficult to be optimized simultaneously. Herein, a novel hierarchical particle–sheet-structured Fe-doped NixP electrocatalyst is developed, which presents abundant interfaces between crystalline particle and amorphous sheet. The OER overpotential is reduced to 204 mV at 20 mA cm−2 current density, while it is reduced to 225 and 231 mV at 100 and 300 mA cm−2, respectively. The Fe-doped NixP electrocatalyst also shows fast reaction kinetics, whose Tafel slope is a remarkable 25 mV dec−1. For an electrolytic cell whose cathode and anode are Pt/C/NF and Fe–NixP/NF, respectively, a mere 1.446 V voltage is necessary to drive a 10 mA cm−2 current density for achieving overall water-splitting property. Notably, it also works stably at considerably high current densities of 500 and 1000 mA cm−2, representing high potential for commercial applications. [ABSTRACT FROM AUTHOR]

Saudi Arabia has developed Saudi Vision 2030, an ambitious plan to reduce the country's dependence on oil by supporting promising private energy organizations and by developing opportunities that contributes to the national economy. In the manufacturing sector, the government is encouraging technology transfers in the renewable energy industries. It is expected to result in the localization of significant parts of the renewable energy value chain in Saudi Arabia. Solar energy systems are proven renewable energy source globally and domestically, it has its long and vast share of experience, from operations and maintenance, to solar data monitoring and gathering. Wide areas had been identified, where this technology can be highly installed and integrated. Components can be manufactured from locally available raw materials to achieve the final products. This study analyzed the key elements of the value chain for producing crystalline silicon solar photovoltaic systems. This paper presents recommendations for localizing this industry in the Kingdom of Saudi Arabia to align with the goals of Saudi Vision 2030. Although these recommendations are based on the environmental conditions of Saudi Arabia, such are also highly relevant for further application to other countries in the Middle East and North Africa region, where widespread energy transitions from fossil fuels to renewable resources are already taking place. [ABSTRACT FROM AUTHOR]

A scintillating crystal's surface reflectance has to be well understood in order to accurately predict and optimize the crystal's light collection through Monte Carlo simulations. In this paper, we measure the inner surface reflectance properties for BGO. The measurements include BGO crystals with a mechanically polished surface, rough-cut surface, and chemically etched surface, and with various reflectors attached, both air-coupled and with coupling compound. The measurements are performed with a laser aimed at the center of a hemispherical shaped BGO crystal. The hemispherical shape eliminates any non-perpendicular angles for light entering and exiting the crystal. The reflected light is collected with an array of photodiodes. The laser can be set at an arbitrary angle, and the photodiode array is rotated to fully cover 2ir of solid angle. The current produced in the photodiodes is readout with a digital multimeter connected through a multi-plexer. The two rows of photodiodes achieve 5-degree by 4-degree resolution, and the current measurement has a dynamic range of 105 : 1. The acquired data was not described by the commonly assumed linear combination of specular and diffuse (Lambertian) distributions, except for a very few surfaces. Surface roughness proved to be the most important parameter when choosing crystal setup. The reflector choice was of less importance and of almost no consequence for rough-cut surfaces. Pure specular reflection distribution for all incidence angles was measured for polished surfaces with VM2000 film, while the most Lambertian distribution for any surface finish was measured for titanium dioxide paint. The distributions acquired in this paper will be used to create more accurate Monte Carlo models for light reflection distribution within BGO crystals. [ABSTRACT FROM AUTHOR]

The article focuses on a study involving liquid crystal interfaces. The author revealed that the Bristol project focused on molecular orientation at the free surface of molecular fluids. He also stressed that the theoretical investigation on surface structure of liquid crystals used molecular cylindrical symmetry as its starting point.

Quasiphase matching (QPM) is a widely used theory in crystal to analyze the character of second-harmonic generation (SHG) emitted from it. Based on the structural features of collagen type I, where the constituted fibrils in collagen function as a crystal which has the structure of two-dimensional (2D) quasicrystalline, in this paper, we use the QPM theory on collagen for SHG emission direction study under the excitation of laser light through a microscope. The effects of numerical aperture NA, as well as the structural parameters, such as QPM order (m,l) and collagen period a=d1+d2 associated with the fibrils diameter (d1), packing density and interfibrils structure (d2), etc., on SHG emission angle φ have been investigated. Our theoretical results show that collagen period a has threshold effect on φ to present forward or backward SHG emission and NA has minor influence on this threshold value a. Collagen period of a has more significant influence on SHG emission angle φ when a is smaller than the threshold value. In reality, we realize that diameter of collagen fibrils d1 plays a major role on forward or backward emission of SHG. Here, for example, (we assume d1=a/2), when d1≤95 nm [(m,l)=(1,0)], the backward SHG shows up at any magnitude of NA, while when d1≥150 nm [(m,l)=(1,0)], SHG presents forward emission feature under all circumstances. Between them, SHG emits from forward direction to backward direction as the increase in NA. The QPM order (m,l) has nonlinear impact on SHG emission angle φ and has different degrees of influence on different collagen period a. Our theoretical results are highly consistent with the experiments results demonstrated by other researchers and provide a proper explanation of the phenomenon of appreciable backward SHG signals appearing in collagen type I. Our established theoretical model of applying QPM theory in 2D quasicrystalline fibrils is therefore confirmed to be a suitable model for dealing with SHG in type I collagen. [ABSTRACT FROM AUTHOR]

In the effort to develop atomistic models capable of accurately describing nanoscale systems with complex interfaces, it has become clear that simple treatments with rigid charge distributions and dispersion coefficients selected to generate bulk properties are insufficient to predict important physical properties. The quantum Drude oscillator model, a system of one-electron pseudoatoms whose “pseudoelectrons” are harmonically bound to their respective “pseudonuclei,” is capable of treating many-body polarization and dispersion interactions in molecular systems on an equal footing due to the ability of the pseudoatoms to mimic the long-range interactions that characterize real materials. Using imaginary time path integration, the Drude oscillator model can, in principle, be solved in computer operation counts that scale linearly with the number of atoms in the system. In practice, however, standard expressions for the energy and pressure, including the commonly used virial estimator, have extremely large variances that require untenably long simulation times to generate converged averages. In this paper, low-variance estimators for the internal energy are derived, in which the large zero-point energy of the oscillators does not contribute to the variance. The new estimators are applicable to any system of harmonic oscillators coupled to one another (or to the environment) via an arbitrary set of anharmonic interactions. The variance of the new estimators is found to be much smaller than standard estimators in three example problems, a one-dimensional anharmonic oscillator and quantum Drude models of the xenon dimer and solid (fcc) xenon, respectively, yielding 2–3 orders of magnitude improvement in computational efficiency. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present a new set of experimental results on the solubility of crystalline bayerite and gibbsite in caustic NaNO media ( I = 0.1-5 mol·kg) from 303 to 363 K, reflecting conditions in the high-level nuclear waste repository at the Hanford site in the USA. The resulting molal solubility constants, K , were combined with some previous literature values and modeled using the SIT and Pitzer ion-interaction models in order to provide a coherent internally-consistent set of data quantifying the thermodynamic dissolution behavior of these aluminum phases. The two models led to similar thermodynamic quantities compatible with those from previous studies for bayerite and gibbsite, and in both cases the differences in the ion-interaction parameters could be taken as being temperature independent. [ABSTRACT FROM AUTHOR]

Amorphous titanium dioxide (a-TiO2) is widely used as a coating material in applications such as electrochemistry and self-cleaning surfaces where its interface with water has a central role. However, little is known about the structures of the a-TiO2 surface and aqueous interface, particularly at the microscopic level. In this work, we construct a model of the a-TiO2 surface via a cut-melt-and-quench procedure based on molecular dynamics simulations with deep neural network potentials (DPs) trained on density functional theory data. After interfacing the a-TiO2 surface with water, we investigate the structure and dynamics of the resulting system using a combination of DP-based molecular dynamics (DPMD) and ab initio molecular dynamics (AIMD) simulations. Both AIMD and DPMD simulations reveal that the distribution of water on the a-TiO2 surface lacks distinct layers normally found at the aqueous interface of crystalline TiO2, leading to an ∼10 times faster diffusion of water at the interface. Bridging hydroxyls (Ti2–ObH) resulting from water dissociation decay several times more slowly than terminal hydroxyls (Ti–OwH) due to fast Ti–OwH2 → Ti–OwH proton exchange events. These results provide a basis for a detailed understanding of the properties of a-TiO2 in electrochemical environments. Moreover, the procedure of generating the a-TiO2-interface employed here is generally applicable to studying the aqueous interfaces of amorphous metal oxides. [ABSTRACT FROM AUTHOR]

The North-South earthquake belt (NSEB) is one of the major earthquake regions in China. The studies of crustal structure play a great role in understanding tectonic evolution and in evaluating earthquake hazards in this region. However, some fundamental crustal parameters, especially crustal interface structure, are not clear in this region. In this paper, we reconstructed the crustal interface structure around the NSEB based on both the deep seismic sounding (DSS) data and the gravity data. We firstly reconstructed the crustal structure of crystalline basement (interface G), interface between upper and lower crusts (interface C) and Moho in the study area by compiling the results of 38 DSS profiles published previously. Then, we forwardly calculated the gravity anomalies caused by the interfaces G and C, and then subtracted them from the complete Bouguer gravity anomalies, yielding the regional gravity anomalies mainly due to the Moho interface. We then utilized a lateral-variable density interface inversion technique with constraints of the DSS data to invert the regional anomalies for the Moho depth model in the study area. The reliability of our Moho depth model was evaluated by comparing with other Moho depth models derived from other gravity inversion technique and receiver function analysis. Based on our Moho depth model, we mapped the crustal apparent density distribution in the study area for better understanding the geodynamics around the NSEB. [ABSTRACT FROM AUTHOR]

This study introduces the development of a novel bio-nano composite via the dispersion of cellulose nanofibers (CNF) in epoxy. The surface of cellulose nanofibers was functionalized using a two-step chemical treatment to enhance dispersion. The interfacial characteristics of CNF were improved using alcohol/acetone treatments. The modified CNF (M-CNF) demonstrated enhanced compatibility and improved dispersion in the epoxy matrix as evidenced by scanning electron microscopy. Based on the analysis of X-ray diffraction patterns, M-CNF did not disturb the crystalline phases at the interface. The results of mechanical testing showed that M-CNF worked as a reinforcing agent in the bio-nano composite. The flexural modulus increased from 1.4 to 3.7 GPa when M-CNF was introduced. A similar trend was observed for tensile strength and impact resistance. The optimum performance characteristics were observed at M-CNF of 0.6%. At higher dosages, some agglomeration was observed, which weakened the interfacial properties. This study promotes sustainability and resource conservation while offering CNF as a sustainable reinforcing agent to develop bio-nano composites. [ABSTRACT FROM AUTHOR]

This paper reports recent theoretical perspectives and experimental results on microstructural evolution during sintering in terms of the interface structure, which is either rough (atomically disordered) or faceted (atomically ordered). The paper presents theoretical predictions and calculations of grain growth during liquid-phase sintering based on crystal growth theories. It is shown that various types of grain growth behavior, which may be normal, abnormal, or stagnant, can appear as a result of the coupling effects of the maximum driving force for growth and the critical driving force for appreciable growth. The predictions are also shown to be valid in the case of solid-state sintering. A number of experimental observations showing the effect of some critical processing parameters have been found to be in excellent agreement with the predictions. Principles of microstructure development (grain growth control) during sintering are suggested. In addition, the effect of the interface structure on densification is briefly described and discussed. [ABSTRACT FROM AUTHOR]

The present paper describes an opto-electronic humidity sensor based on thin film of zinc oxide prepared by pulsed laser deposition method. Being optical in nature it gives electromagnetic disturbance-free monitoring. The sensing element is a right-angled isosceles prism with its base coated with ZnO thin film. Films have been characterized by XRD, SEM, and optical transmission. Film grown with substrate at room temperature is amorphous whereas that grown at elevated temperature is single crystalline with grain size 38.52 nm. Film deposited at room temperature is sensitive to humidity over a wide range i.e. 5–90RH% while that deposited at elevated temperature is found to be insensitive to humidity. The sensor shows better sensitivity for higher range of humidity. The response and recovery time of the sensor element have also been evaluated. This sensor configuration can be used for on-line applications and in-situ monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] • Crystalline Ni(OH) 2 /Amorphous NiMoS electrocatalyst were designed and synthesized by two-step hydrothermal process. • The as-obtained material shows excellent hydrogen evolution over all pH ranges. • The synergistic mechanism and the role of crystalline Ni(OH) 2 and amorphous NiMoS was elucidated. Designing and fabricating efficient electrocatalysts is a practical step toward the commercial application of the efficient hydrogen evolution reaction (HER) over all pH ranges. Herein, novel Ti@Ni(OH) 2 -NiMoS heterostructure with interface between crystalline Ni(OH) 2 and amorphous NiMoS was rationally designed and fabricated on Ti mesh (denoted as Ti@Ni(OH) 2 -NiMoS). Acid etching and calcination experiments helped in accurate elucidation of the synergistic mechanism as well as the vital role on crystalline Ni(OH) 2 and amorphous NiMoS. In acidic solutions, the HER performance of Ti@Ni(OH) 2 -NiMoS was mainly attributed to the amorphous NiMoS. In neutral, alkaline, and natural seawater solutions, the HER performance was mainly determined by the synergistic interface behaviors between the Ni(OH) 2 and NiMoS. The crystalline Ni(OH) 2 accelerated water dissociation kinetics, while the amorphous NiMoS provided abundant active sites and allowed for fast electron transfer rates. To deliver current densities of 10 mA·cm−2 in acidic, neutral, alkaline, and natural seawater solutions, the Ti@Ni(OH) 2 -NiMoS required overpotentials of 138, 198, 180 and 371 mV, respectively. This paper provides general guidelines for designing efficient electrocatalyst with crystalline/amorphous interfaces for efficient hydrogen evolution over all-pH ranges. [ABSTRACT FROM AUTHOR]

The degradation of microplastics in relation to marine pollution has been receiving increasing attention. Because the spherulites that comprise microplastics have a highly ordered lamellar structure, their decomposition is thought to involve a lamellar structure collapse process. However, even in the simplest case of an order–disorder transition between lamellae and melt upon heating, the microscopic details of the transition have yet to be elucidated. In particular, it is unclear whether nucleation occurs at defects in the crystalline portion or at the interface between the crystalline and amorphous portions. To observe the transition in molecular simulations, an approach that distinguishes between the crystalline and amorphous structures that make up the lamella is needed. Local order parameters (LOPs) are an attempt to define the degree of order on a particle-by-particle basis and have demonstrated the ability to precisely render complex order structure transitions during phase transitions. In this study, 274 LOPs were considered to classify the crystalline and amorphous structures of polymers. Supervised machine learning was used to automatically and systematically search for the parameters. The identified optimal LOP does not require macroscopic information such as the overall orientation direction of the lamella layers but can precisely distinguish the crystalline and amorphous portions of the lamella layers using only a small amount of neighboring particle information. [ABSTRACT FROM AUTHOR]

In this paper, effect of emulsification processes on the properties of Pickering emulsions stabilized by organomontmorillonites (OMts) was studied. Results of micro-morphology and X-ray diffraction showed that the structure of OMt in emulsion depended on the emulsification processes and had an effect on the stability of emulsion. We propose a schematic diagram to reveal the relationship between emulsification processes-OMt laminates structure-stability of Pickering emulsion. In emulsion prepared by ultrasonic, OMt showed uniform dispersion, loose structure, and irregular crystalline. In emulsion prepared by vortex mixing method, OMt illustrated stacking and coagulation structure. In emulsion prepared by microwave method, OMt showed interacting structure and had a little interaction with oil/water interface, and thus the properties of emulsion prepared by microwave was weakly related to oil/water ratios. Emulsification processes had a profound effect on the structure of OMt and stability of Pickering emulsion, which can be used as a trigger to prepare emulsion for various applications. [ABSTRACT FROM AUTHOR]

• • The large-sized 4H-SiC single crystals were grown via sublimation technique. • • Impact of crucible structure on growth behavior was systematically investigated. • • SiC crystal grown in specific crucible exhibits superior characteristics. Silicon carbide (SiC), as the wide bandgap semiconductor, has gradually attracted attention from investigators due to the excellent integrated performance, widely recognized as a revolution in the electronic devices. For these applications, it is crucial to prepare the high-quality SiC crystal ingot by optimizing growth parameters and crucible structures. In this study, the effect of TaC coating and graphite paper on the growth process of SiC ingot were investigated compared to the growth in conventional graphite crucible through modeling and experiment. We demonstrated that the grown crystal using TaC-coated graphite relay ring and graphite paper surrounded the inner wall of powder container shows the superior characteristics in terms of the crystalline perfection and interface shape. In addition, the new crucible structure can provide a low-cost solution to prepare SiC crystal ingot using PVT method. [ABSTRACT FROM AUTHOR]

[Display omitted] The CSL/DSCL model for interfaces in crystalline materials offers a unified framework to study interface dislocations in phase boundaries and disconnections in grain boundaries. The model relies on the existence of a coincidence relation between the two lattices that meet at an interface. The model's ability to quantitatively predict the thermodynamics and kinetics of interfaces has been demonstrated for a limited set of symmetric tilt grain boundaries (STGBs) in cubic materials and twin boundaries. However, the lack of a general framework of interface defects prevents its applicability to arbitrary rational boundaries. In this paper, we present a mathematical framework based on the Smith normal form (SNF) for integer matrices to study the bicrystallography of rational phase and grain boundaries. One of the main results of the paper is a constructive proof of the invariance of the coincident site lattice (CSL) under discrete relative displacements of the parent lattices (of possibly different kind) by a displacement shift complete lattice (DSCL) vector. In addition, we obtain necessary and sufficient conditions on two lattices, related by not only rotations but also lattice distortions, for the existence of a coincidence relation. We first apply these results to explore coincidence relations in arbitrary phase boundaries, and study interface dislocations. In particular, we demonstrate the framework for a phase boundary formed by a strained hexagonal lattice and a square lattice. As a second application, we show how to enumerate all possible (geometric) disconnection modes in arbitrary rational grain boundaries, including glide and non-glide modes in both STGBs and asymmetric-tilt grain boundaries (ATGBs). The constructive nature of the framework lends itself to an algorithmic implementation based exclusively on integer matrix algebra to construct all interfaces that admit CSLs up to a prescribed size, and determine disconnection modes in grain boundaries. We demonstrate the use of SNF bicrystallography on selected bicrystal misorientation axes/angles in face-centered cubic (fcc), body-centered cubic (bcc), and hexagonal (hex) lattices. [ABSTRACT FROM AUTHOR]

We report different growth modes and corresponding magnetic properties of thin EuSe films grown by molecular beam epitaxy on BaF2, Pb1−xEuxSe, GaAs, and Bi2Se3 substrates. We show that EuSe grows predominantly in the (001) orientation on GaAs(111) and Bi2Se3, but along the (111) crystallographic direction on BaF2 (111) and Pb1−xEuxSe (111). High resolution transmission electron microscopy measurements reveal a sharp and highly crystalline interface for both (001) and (111) EuSe films. In agreement with previous studies, ordered magnetic phases include antiferromagnetic, ferrimagnetic, and ferromagnetic phases. In contrast to previous studies, we found a strong hysteresis of the antiferromagnetic–ferrimagnetic transition. The ability to grow epitaxial films of EuSe on Bi2Se3 and of Bi2Se3 on EuSe enables further investigation of interfacial exchange interactions between various phases of an insulating metamagnetic material and a topological insulator. [ABSTRACT FROM AUTHOR]

In this paper, the impact of iron contamination on the conversion efficiency of single-crystalline p-type silicon solar cells is investigated by means of the combination of numerical simulations and experimental data, taking into account the more recent results about the properties of iron in single-crystalline silicon. Numerical simulations highlight the fill factor losses due to the injection-level dependence of the bulk lifetime, which attenuates the decrease of the open circuit voltage and thus that of the solar cell conversion efficiency with iron concentration. Gettering and hydrogenation effects are quantified by means of experimental results obtained from voluntarily contaminated solar cells and integrated in the simulations. The results show that iron appears to be a metallic impurity rather well tolerated in p-type single-crystalline silicon solar cells, because its injection-level dependent bulk lifetime, like its abilities to be gettered and to be passivated by hydrogenation, limits its influence on the solar cell conversion efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • The crystallization process of amorphous YAG oxide is investigated from an atomic point of view. • The crystallization proceeds on the surface and interior of the amorphous YAG separately, and which show the preferential crystallization of the surface atoms. • Some atoms in the amorphous phase were controlled by the periodic potential field of the crystal atoms and produced dynamically changing semi-ordered structures at the amorphous/crystalline interface with mainly concentrated within 1–2 nm from the interface. The transformation from amorphous materials to crystals and the corresponding microscopic mechanism have become a research focus in materials science, condensed matter physics, and biophysics etc. In this paper, taking Y 3 Al 5 O 12 (YAG) as an example, the crystallization process of amorphous YAG oxide is investigated from an atomic point of view through the combination of spherical aberration-corrected transmission electron microscopy (SCTEM) with an in situ heating method, and the morphology and structural evolution of the surface and interface are explored. It is observed that the crystallization proceeds on the surface and interior of the amorphous YAG separately. Through atomic-scale imaging, it is determined that semi-ordered structures are formed in a few atomic layers at the amorphous/crystalline interface and that the structural transformation process from the amorphous to the semi-ordered state and then to the crystal structure may be the main reason for the multiple stages of the crystallization of amorphous oxides. This study demonstrates the mechanism of the amorphous-to-crystal transformation on the atomic scale and contributes to gaining a better understanding of the crystallization process of bulk oxides, especially complex metal oxides. [ABSTRACT FROM AUTHOR]

A major challenge with water splitting technology is to develop highly active and stable electrocatalysts for the oxygen evolution reaction (OER). IrO2 – based electrocatalysts are one of the most active electrocatalysts for proton exchange membrane (PEM) electrolysers, due to their excellent activity for the OER in acidic conditions. However, IrO2 often suffers from dissolution during electrolysis due to phase transitions into more soluble forms. Herein, a range of electrodeposited IrO2 films annealed to different temperatures of up to 500°C are prepared to understand the influence that crystalline/amorphous interfaces have on performance during accelerated degradation tests in concentrated acidic solutions. This study showed that an IrO2 film annealed at 300 °C exhibited the highest catalytic activity with a low overpotential of 150 mV at 10 mA cm−2, the smallest Tafel slope of 51 mV dec−1, with a less progressive decay in activity over a period of 8 h of accelerated degradation testing. This contrasts with both fully amorphous or more crystalline IrO2 films that decayed much more rapidly within 1 h of testing indicating the role that amorphous/crystalline regions have on OER performance. [ABSTRACT FROM AUTHOR]

Conducting oxide interfaces have attracted considerable attention, motivated by both fundamental science and potential for oxide electronic devices. An important gap for maturing such device technology is scalability and routes to control the electronic properties, which can narrow the device engineering space. Here, we demonstrate and explain the mechanisms of highly tunable conductive oxide interfaces. We synthesized amorphous--crystalline Al2O3/SrTiO3 interfaces using the scalable and industry-compatible atomic layer deposition (ALD) technique. An NH3 plasma pretreatment is employed in the ALD chamber, and its duration is used as a tuning parameter for the electrical properties, where a span of three orders of magnitude in the sheet resistance is observed at room temperature. For the most conductive sample, our results are comparable to the highest carrier density values reported for all-crystalline oxide interfaces prepared with state-of-the-art epitaxial growth techniques, such as pulsed laser deposition. We pinpoint the origin of conductivity to oxygen vacancies caused by the SrTiO3 reduction by the NH3 plasma pretreatment. These results present a simple, scalable, and industry-compatible route for realizing conductive oxide interfaces, with a broad parameter space, offering a versatile and flexible toolkit for oxide device engineering. [ABSTRACT FROM AUTHOR]

The compositions in the ternary chalcogenide systems from the demarcation region between the glass-formation domain (GFD) and the partially or fully crystalline formation domain seem to exhibit outstanding properties. We have shown in this paper that the compositions with the best memory-switching properties are situated at the border of the GFD in many systems. One can use this correlation to find new phase-change materials with better switching properties or to discover GFDs that were not observed yet. [ABSTRACT FROM AUTHOR]

In this paper, a variational approach is proposed to study the response of a single-crystalline magnetic shape memory alloy (MSMA) sample subject to external forces and magnetic fields. Especially, some criteria are derived to model the (quasi-static) movements of twin interfaces in the sample. By considering the compatibility condition, twin interfaces between two martensite variants are found to be flat planes with given normal vectors. To adopt the variational method, a total energy functional for the whole magneto-mechanical system is proposed. By calculating the variations of the total energy functional with respect to the independent variables, the equilibrium equations and the evolution laws for the internal variables can be derived. By further considering the variation of the total energy functional with respect to the variant distribution, some criteria for twin interface movements can be derived. The governing system of the current model is then formulated by composing the equilibrium equations, the evolution laws for the internal variables and the twin interface movement criteria. To show the validity of the governing system, some analytical results are constructed under certain simplified conditions, which can be used to simulate the magneto-mechanical response of the MSMA sample. [ABSTRACT FROM AUTHOR]

The paper discusses the wear resistance, friction coefficient, and structure of friction surfaces of submicron crystalline Y-TZP-AlO composite rubbed against a steel disk counterface at a pressure of 5 MPa in a range of sliding speeds from 1 to 20 m/sec. It is shown that, starting at 2 m/sec, the friction surface is subdivided by a crack network into separate regions within which local spalling occurs at the maximum wear rate and a sliding speed of 5 m/sec. X-ray diffraction reveals inversion (with respect to the initial state) of the peak intensities of the tetragonal phase with random crystalline grain orientation. The degree of this inversion increases with sliding speed. These results are discussed in terms of the effects exerted by the reorientation of martensite-free deformation twins in the tetragonal phase and the formation of a quasi-liquid film on the wear resistance of Y-TZP-AlO. [ABSTRACT FROM AUTHOR]

The interfacial stiffness for nematic–smectic B (nm–smB) interface in a liquid crystalline (LC) material is calculated using Capillary Wave Theory (CWT) and molecular dynamics simulations. The Gay–Berne (GB) pair potential with parameters κ, κ′, μ, and ν equal to 3, 5, 2, and 1 is used to model the LC material. Using a smart three-step recipe, we have obtained an nm–smB phase coexistence in our simulations where the nm and smB directors are nearly parallel to each other and perpendicular to the interface normal. The density profiles are used to compute the nm–smB coexisting density range, the interfacial width, and its position. The smectic phase is differentiated from the nematic phase by using the local bond order parameter (q6q6), which has helped us to demonstrate that the interface is indeed rough. Finally, the interfacial stiffness of the nm–smB interface is computed by following the CWT analysis and is found to be γ ̃ n m − s m B = 0.398 61 k B T / σ e e 2 = 0.044 29 / σ s s 2 , where σee and σss are the length and diameter of the GB LC particles. [ABSTRACT FROM AUTHOR]

• Highlighting the immunity behavior of a-Si:H/c-Si solar cell against the interfacial defects. • Analytical modelling of the impact of a triangular texture morphology and a double antireflection coating layer. • Novel design criterion via Gray Wolf Optimization algorithm (GWO). In this paper, we present an analytical study of the impact of light trapping and multilayer antireflection coating (ARC) on the electrical characteristics of n(a-Si:H)/i(a-Si:H)/p(c-Si)/p+(C-Si) heterojunction solar cells with intrinsic thin layer (SHJ). The developed analytical model considers a triangular texture morphology of the solar cell top surface and a double ARC layer. This model serves as a fitness function to optimize the device reliability against the interfacial traps using Grey Wolf optimization approach (GWO). The optimized solar cell reveals a high short circuit current I SC = 47.9 mA, an open circuit voltage V OC = 0.56 V, fill factor FF = 74.72% and a conversion efficiency improvement in the order of 30% over conventional planar solar cells efficiency. Not only the optimized SHJ solar cell exhibits higher performance in terms of figure of merits, but also shows superior interfacial traps reliability at the amorphous/crystalline interface. This reliability enhancement is due to a better surface texture control and intrinsic thin film layer tuning provided by GWO approach. [ABSTRACT FROM AUTHOR]

This paper presents a microstructural study of laser micro-processed high-purity CuZrAl alloys prepared by arc melting and Cu-mould casting. Microprocessing of the CuZrAl alloy was performed using a Rofin DC-015 diffusion-cooled CO slab laser system with 10.6-μm wavelength. The laser was defocused to a spot size of 0.2 mm on the sample surface. The laser parameters were set to give 300- and 350-W peak power, 30% duty cycle and a 3000-Hz laser pulse repetition frequency (PRF). About 100-micrometer-wide channels were scribed on the surfaces of disk-shaped amorphous and partially crystalline samples at traverse speeds of 500 and 5000 mm/min. These channels were analysed using scanning electron microscopy (SEM) and 2D stylus profilometry. The metallographic study and profile of these processed regions are discussed in terms of the applied laser processing parameters. The SEM micrographs showed that striation marks developed at the edge and inside these regions as a result of the laser processing. The results from this work showed that microscale features can be produced on the surface of amorphous Cu-Zr-Al alloys by CO laser processing. [ABSTRACT FROM AUTHOR]

From 22,791 mutants of a cellulase hyper-producing strain of Trichoderma reesei ( Hypocrea jecorina), ATCC66589, as the parent, we selected two mutants, M2-1 and M3-1, that produce cellulases in media containing both cellulose and glucose. The mutation enabled the mutants to produce cellulases, which were measured as p-nitrophenyl β- d-lactopyranoside-hydrolyzing activities, in media with glucose as a sole carbon source, although M2-1 exhibited different sensitivities to glucose from M3-1. When the mutants were grown for 8 days on a medium with cellulose as a sole carbon source, the filter-paper-degrading activities (FPAs) per gram of cellulose were 257 and 281 U for M2-1 and M3-1, respectively, values that were 1.1–1.2 times higher than that of the parental strain. Cellulase production by M2-1 and M3-1 on a medium with a continuously fed mixture of glucose and cellobiose resulted in 214 and 210 U of FPA/gram carbon sources, respectively, whereas less efficient production (140 U of FPA/gram carbon source) was achieved by the parental strain. The improved cellulase productivity of the mutants allows us to use glucose as a carbon source for efficient on-site production of cellulases with quality/quantity-controlled feeding of soluble carbon sources and inducers. [ABSTRACT FROM AUTHOR]

Many activated phenomena, including solid state diffusion in crystals and polymers, dielectric relaxation, conduction and thermally stimulated processes in polymers, and electronic conduction in amorphous semiconductors obey the compensation law or Meyer-Neldel rule. In the present paper, we discuss the results of investigation into the compensation effect observed under isothermal crystallization in glassy Se70Te30−xSbx alloys. It is found that the relation between the pre-exponential factor Ko and activation energy of crystallization Ec follows the Meyer-Neldel rule for the alloys studied. [ABSTRACT FROM AUTHOR]

The crystal structure of methyl α‐d‐mannofuranoside was determined by X‐ray crystallography. The C‐1–C‐2, C‐2–C‐3, C‐3–C‐4, C‐4–O and O‐4–C‐1 distances within the furanoside ring are 1.513(2), 1.523(2), 1.516(2), 1.445(2) and 1.422(2) Å, respectively. The hydrogen bonding consists of O–H–O interactions which include the anomeric oxygen but exclude the ring oxygen atom. The two hydroxyls OH‐6 and OH‐2 are H‐bond acceptors and donors with H···O distances of 1.92–1.93 Å, whereas the OH‐3 and OH‐5 are only H‐bond donor [H···O distance of 2.04(2) Å]. Additionally, OH‐6 participates in a weak hydrogen bond to the anomeric oxygen [H···O distance of 2.19(3) Å]. The crystalline methyl α‐d‐mannofuranoside adopts an 3E ring conformation. The analysis of 13C CPMAS NMR chemical shifts for solid methyl α‐d‐mannofuranoside confirm such H‐bonding pattern. †This paper is dedicated to Professor Gérard Descotes on the occasion of his 70th birthday. [ABSTRACT FROM AUTHOR]

Microstructures and mechanical properties of Ni matrix composites reinforced with amorphous SiO 2 particles by in-situ pyrolysis of polycarbosilane (PCS) coated on Ni powders were studied in this paper. The submicron spherical amorphous SiO 2 particles instead of traditional SiC uniformly distributing in the composites result from the generated silicon source by PCS pyrolysis combined with oxygen impurity in the preparation. The prepared composites achieve high yield strength, 172 MPa, and ultimate tensile strength, 494 MPa, as well as outstanding ductility, total elongation 28.4 %, which is improved 13.9 %, 50.6 % and 160.6 % compared with those for pure Ni samples, respectively. The effects of solid solution strengthening, grain refinement strengthening, reinforcement particle strengthening and dislocations behavior of at amorphous/crystalline interface on the combination of high strength and ductility of the composites were discussed. [Display omitted] • Amorphous SiO 2 reinforced Ni matrix composites were fabricated by in-situ pyrolysis of polycarbosilane coated on Ni powders. • Amorphous SiO 2 instead of crystalline SiC formed by the combination of silicon generated in the pyrolysis with oxygen. • The composites exhibit a combination of excellent tensile strength and ductility. [ABSTRACT FROM AUTHOR]

Detailed analysis of Burgers vectors and line directions has been carried out on three types of dislocation defect (called X, Y and single loops) formed in lowmisfit GexSi1-x/Si(001) heterostructures, grown under conditions of planar interface growth. The X and Y defects originate from small prismatic vacancy half-loops nucleated at visible precipitates at the strained-layer-Si substrate interface. The single-loop defects also originate from small vacancy character half-loops usually nucleated at the interface but also sometimes within the strained layer. After growth, none of the dislocations lies in glide planes, and all three dislocation structures have to be transformed into glissile configurations before they can generate strain-relieving dislocations. The mechanism controlling this sessile/glissile transformation is climb by vacancy absorption. This corresponds to the nucleation stage for the generation of misfit dislocations observed by Houghton and is consistent with the experimental results of Stirpe et al. who found a reduction in thenucleation rates during rapid thermal anneals after Si irradiation at room temperature of the as-grown samples. The paper discusses the driving forces controlling the formation of the observed structures, and their sessile-glissile transformation. [ABSTRACT FROM AUTHOR]

The influence of uniaxial elastic strain of the Ni lattice on the intensity of mutual diffusion at a solid–liquid contact of Ni and Al has been studied by the molecular dynamics method. In all the cases under consideration, the intensity of diffusion has been found to increase and decrease upon extension and compression, respectively, which is related to a corresponding change in the free volume affecting to a great extent the diffusion mobility of atoms. It has been established that the intensity of mutual diffusion in the case of the (111) interface orientation relative to the Ni lattice is higher in comparison with the (001) orientation. This difference is explained by the different energies of Ni atoms in the aluminum phase and incorporated in the interface of crystalline nickel for both cases. [ABSTRACT FROM AUTHOR]

Phase-Change Materials (PCMs) are widely applied in dynamic optical modulation due to the dramatic changes in their complex refractive index caused by temperature variation. As the functionality varies, the application of a single PCM cannot meet the compact, efficient and broadband needs of optical modulators. In this work, we combine vanadium dioxide (VO2) and a chalcogenide (Ge2Sb2Te5 (GST) or In3SbTe2 (IST)) to obtain a VO2–GST/IST multiple-stack film that is optimized by a genetic algorithm. This film has a wide spectrum and high modulation properties with three self-switchable modes varied by temperature, including transmission, absorption and reflection. The optimal results are an average normal transmittance, absorbance, and reflectance of 0.76, 0.91, 0.86 in 3–5 μm and 0.72, 0.90, 0.90 in 8–14 μm under different temperature ranges. The film enhances the transmission and absorption properties due to the formation of anti-reflective coating and Fabry–Perot resonance. Compared with GST, the film maintains high reflectance due to the metal-like interface reflection of crystalline IST, which exhibits metallic properties. For different polarization states, the film demonstrates great directional insensitivity when the incidence angles vary from 0° to 60°. The designed self-adaptive multistage infrared radiative thermo-optic modulator has promising implications for optical fuse, fiber-optic communication and energy storage fields. [ABSTRACT FROM AUTHOR]

Raman spectroscopy has proven its effectiveness as a highly informative and sensitive method for the nondestructive analysis of layered nanostructures and their interfaces. However, there is a lack of information concerning the characteristic phonon modes and their activity in Si/SiO2 nanostructures. In order to overcome this problem, the phonon states and Raman spectra of several Si/SiO2 superlattices (SL) with layer thicknesses varied within 0.5–2 nm are studied using DFT-based computer modeling. Two types of structures with different interfaces between crystalline silicon and SiO2 cristobalite were studied. A relationship between the phonon states of heterosystems and the phonon modes of the initial crystals was established. Estimates of the parameters of deformation potentials are obtained, with the help of which the shifts of phonon frequencies caused by elastic strains in the materials of the SL layers are interpreted. The dependence of intense Raman lines on the SL structure has been studied. Several ways have been proposed to use this information, both for identifying the type of interface and for estimating the structural parameters. The obtained information will be useful for the spectroscopic characterization of the silicon/oxide interfaces. [ABSTRACT FROM AUTHOR]

Molybdenum substitution by chromium in ZrCr 1-x NiMo x alloys produces the segregation of Zr x Ni y phases, ZrCr 2 and ZrMo 2 Laves phases as it was stated in Part I of this paper. In order to study the contribution of these phases in ZrCr 1-x NiMo x alloys performance, secondary Zr 9 Ni 11 and Zr 7 Ni 10 , together with ZrCr 2 and ZrMo 2 Laves phases were synthesized and their crystalline structures determined with XRD patterns. Zr 7 Ni 10 exhibits an orthorhombic structure, whereas Zr 9 Ni 11 depicts a tetragonal structure. ZrCr 2 presents a hexagonal structure (C14), while ZrMo 2 depicts a cubic structure (C15). ZrCr 2 shows zero discharge capacities, while ZrMo 2 exhibits a first capacity value of 245 mAh g −1 . Zr 9 Ni 11 and Zr 7 Ni 10 phases exhibit maximum discharge capacities of 119 and 157 mAh g −1 , respectively. Theoretical results show that the hydride stability for ZrCr 2 is larger than that for ZrMo 2 . However, the great hydrogen storage capacity yields a slower desorption kinetics since it requires a considerable de-hydrogenation energy. The opposite effect is observed for the proposed hexagonal structure ZrMo 2 . The 100% charge of the alloys shows different results for the hydrogen evolution reaction. Zr 7 Ni 10 phase depicts a better performance since the required potentials are lower than −1.05 V. There is a change in the rate determining step ( rds) from a chemical recombination of surface hydrogen (Tafel pathway) in Zr 7 Ni 10 to a fast first electron transfer (Volmer step) for Zr 9 Ni 11 . Thus, the rds is strongly affected by the type of secondary phase dominant in each sample, being Zr 7 Ni 10 the most favorable. [ABSTRACT FROM AUTHOR]

The orientation ratio (OR) is a key issue to achieve high density in longitudinal recording media. Recent recording media have seed layers which exclusively promote small grain growth of the recording layer. In this paper, the effect of seed layers on OR was investigated by the use of various seed materials deposited twice. OR tends to decrease as the thickness of the seed layer is increased; however, the degree of decrease is quite different with seed material. A seed material with small Young’s modulus is preferable for a large OR. These results suggest that OR depends on the interface stress which is relieved as seed layer thickness is increased. Moreover, the relation between the stress in the seed layer and OR was also considered with a multilayer model. [ABSTRACT FROM AUTHOR]

Crystallization processes of amorphous germanium–tin (GeSn) under low-energy electron-beam irradiation were examined using transmission electron microscopy (TEM). Freestanding amorphous GeSn thin films were irradiated with a 100 keV electron beam at room temperature. The amorphous GeSn was athermally crystallized by electron-beam irradiation, when the electron flux exceeded the critical value. Heterogeneous structures consisting of nano- and micro-crystallites were formed after crystallization of amorphous GeSn with ∼24 at. % Sn in the as-sputtered amorphous state. In situ TEM observations of structural changes under electron-beam irradiation revealed that random nucleation and growth of nanocrystallites occur at the early stage of crystallization, followed by rapid formation of micro-grains surrounding the nanocrystals. It has been suggested that the growth of micro-grains progresses via supercooled liquid Sn at the amorphous/crystalline interface. The resultant GeSn grains with a size of a few micrometers contained ∼15 at. % Sn, much larger than the solubility limit of Sn in Ge (∼1 at. % Sn). [ABSTRACT FROM AUTHOR]

We investigate how varying molecular topology of polymers influences crystallization in thin polymer films. In particular, we simulate linear and star polymers of fixed mass having a progressively increasing number of arms (f ≤ 16) in a system where the linear polymer exhibits crystallization in a thin film geometry, but no apparent crystallization in the corresponding bulk material. The degree of crystallization of the polymer film at long times decreases progressively with increasing f, and no crystallization is observed beyond f = 8. Crystallization for smaller values of f develops as a sigmoidally shaped wavefront initiating from the supporting crystalline interface. We suggest that large shape fluctuations and the competition of length scales of star polymers with high f lead to inhibited crystallization. [ABSTRACT FROM AUTHOR]

ZSR-P loaded nano-TiO 2 composite photocatalysts (TiO 2 /ZSR-P) have been prepared by the sol–gel method using the by-product Zr-containing silica residue (ZSR) as precursors during the production process of zirconium oxychloride, the structure and properties of TiO 2 /ZSR-P were characterized in this paper. The results showed that the TiO 2 /ZSR-P composite photocatalysts were characterized by the uniform loading of nano-TiO 2 on the surface of amorphous SiO 2 particles in ZSR-P. TiO 2 and SiO 2 were combined by forming -Ti-O-Si- bonds at the interface and the crystalline structure of TiO 2 powders was identified a mixed phase of anatase and rutile, its loading amount was 17.14%, the particle size raged from 7 to 12 nm. The degradation rate of TiO 2 /ZSR-P to the concentration of 5 ppm and 10 ppm methyl orange solution reached 99.52% and 100% respectively after 140 min of ultraviolet irradiation, and it still maintained stable performance after repetitive-use of the catalyst for 4 times. [ABSTRACT FROM AUTHOR]

The oxide-semiconductor interface is a key element of MOS transistors, which are widely used in modern electronics. In silicon electronics, SiO2 is predominantly used. The miniaturization requirement raises a problem regarding the growing of heterostructures with ultrathin oxide layers. Two structural models of interface between crystalline Si and cristobalite SiO2 are studied by using DFT-based computer modelling. The structures of several Si/SiO2 superlattices (SL), with layer thicknesses varied within 0.5–2 nm, were optimized and tested for stability. It was found that in both models the silicon lattice conserves its quasi-cubic structure, whereas the oxide lattice is markedly deformed by rotations of the SiO4 tetrahedra around axes perpendicular to the interface plane. Based on the analysis of the calculated total energy of SLs with different thicknesses of the layers, an assessment of the interface formation energy was obtained. The formation energy is estimated to be approximately 3–5 eV per surface Si atom, which is close to the energies of various defects in silicon. Elastic strains in silicon layers are estimated at 5–10%, and their value rapidly decreases as the layer thickens. The elastic strains in the oxide layer vary widely, in a range of 1–15%, depending on the interface structure. [ABSTRACT FROM AUTHOR]

Complexes (bmim)2[Cu3(μ3-Cl)2(μ-pz)3Cl3] (1), (bmim)[Cu3(μ3-OH)(μ-pz)3Cl3] (2) and (bmim)2[Cu3(μ3-OH)(μ-Cl)(μ-pz)3Cl3] (3) were synthesized (bmim+ = 1-butyl-3-methylimidazolium, pz− = pyrazolato anion). Dianionic complexes 1 and 3 were obtained as crystalline solids, whereas the monoanionic complex 2 was obtained as a viscous paste. Magnetic susceptibility and X-band EPR studies revealed intramolecular ferromagnetic interactions for 1 with small magnetoanisotropy in its ground state (D3/2∼ 10−3 cm−1) and intramolecular antiferromagnetic interactions for 2 and 3 (−285 and −98 cm−1 average J, respectively) with important magnetic anisotropy in their ground states stemming from a combination of low magnetic symmetry and antisymmetric exchange interactions. Thermal studies revealed a clear melting point of 140 °C for 1, which is lower than that of its PPN+ and Bu4N+ analogues (1PPN and 1Bu4N, respectively, PPN+ = bis(triphenylphosphine)iminium). Upon cooling, 1 remains molten down to 70 °C. Mixtures of the salts 1, 1PPN and 1Bu4N, exhibited modified melting behaviours, with the mixtures exhibiting lower melting points than those of either of their pure components. [ABSTRACT FROM AUTHOR]

Neutron total scattering of disordered crystalline materials provides direct experimental access to the local (short-range) structure. The ways in which this local structure agrees (or disagrees) with the long-range crystal structure can provide important insight into structure-property relationships. High-pressure neutron diffraction using a Paris-Edinburgh (P-E) pressure cell allows experimenters to explore the ways in which materials are affected by pressure, can reveal new synthetic routes to novel functional materials and has important applications in many areas, including geology, engineering and planetary science. However, the combination of these two experimental techniques poses unique challenges for both data collection and analysis. In this paper it is shown that, with only minor modifications to the standard P-E press setup, high-quality total scattering data can be obtained from crystalline materials in the gigapascal pressure regime on the PEARL diffractometer at ISIS. The quality of the data is assessed through the calculation of coordination numbers and the use of reverse Monte Carlo refinements. The time required to collect data of sufficient quality for detailed analysis is assessed and is found to be of the order of 8 h for a quartz sample. Finally, data from the perovskite LaCo0.35Mn0.65O3 are presented and reveal that PEARL total scattering data offer the potential of extracting local structural information from complex materials at high pressure. [ABSTRACT FROM AUTHOR]