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Complex oxide heterointerfaces and heterostructures have demonstrated enormous emergent phenomena over the last decades, attributed to the reconstructions of mis‐matched crystalline structure, polarity, and spin ordering across the heterointerfaces. This work employs the heterostructures of La0.7Sr0.3MnO3 and CaFeO2.5 as model system to demonstrate an interface‐specific oxygen migration/reconstruction across the interfaces due to the mismatched chemical potential, which dramatically influences the ferromagnetic and electronic states of La0.7Sr0.3MnO3 layer. Specifically, the alternative stacking of octahedral (Oh) and tetrahedral (Td) layers in CaFeO2.5 are used to form two distinct heterointerfaces, namely the Oh‐Td and the Oh‐Oh interfaces with the adjacent La0.7Sr0.3MnO3 layer. Interestingly, the oxygen ion migrates toward opposite directions across the interface for these two cases, in which the CaFeO2.5 layer acts as an “oxygen pump” and manipulates the oxygen contents of its adjacent La0.7Sr0.3MnO3 layers. Such manipulation leads to a dramatically changed ferromagnetic transition temperature for the heterostructure with the Oh‐Td and Oh‐Oh interface. This work establishes a feasible and efficient strategy to control the oxygen ionic distribution through atomic‐scale interface design and opens up new opportunities to exploit emergent states at the complex oxide heterostructures through selective oxygen ion evolution. [ABSTRACT FROM AUTHOR]

Benefiting from high safety, low cost, and competitive energy density, aqueous zinc ion batteries (AZIBs) have emerged as very promising technology for grid energy storage. However, the lifetime of AZIBs is severely affected by uncontrolled zinc dendritic growth and undesirable side reaction. To address the problem, natural aluminum silicate hydroxide covered glass fibers separator (AlSi‐GF) is prepared herein using a simple spraying method. Aluminum silicate hydroxide is a complex oxide, where a large number of adsorption sites can adsorb Zn2+ and guide its deposition process. In particular, the Maxwell–Wagner polarization of aluminum silicate hydroxide under an applied electric field contributes to homogenizing the electric field distribution around the interface, thereby modulating zinc deposition and reducing the nucleation overpotential. Impressively, AlSi‐GF separator enables high‐performance zinc‐metal batteries. The symmetric battery with AlSi‐GF separator has a stable voltage polarization and an ultra‐long cycle life of 2280 h at a current density of 1 mA cm−2, and the Zn//V2O5 full cell based on AlSi‐GF separator can exhibit a high specific capacity of 123 mAh g−1 after 1500 cycles at 1 A g−1. This study provides new insights into the design of reliable and cost‐effective separators for metal anodes in energy storage devices. [ABSTRACT FROM AUTHOR]

Oxygen coordination and vacancy ordering play an important role in dictating the functionality of complex oxides. In this work, an unconventional layering of oxygen ions in a mixed conductor SrCo1-xFexO3-δ (SCFO) thin film grown epitaxially on SrTiO3 (STO) is reported. Scanning transmission electron microscopy (STEM) reveals alternating layers of oxygen deficiency along the growth direction, with the oxygen-rich layer correlated with the neighboring Co,Fe-site intensity, and contraction of the Sr–Sr distance. Density functional theory (DFT) calculations and STEM image simulations support the emergence of periodic (Co,Fe)O6 and (Co,Fe)O4/(Co,Fe)O5 layers, an ordering that is also sensitive to the Co:Fe ratio. [ABSTRACT FROM AUTHOR]

Low-dimensional magnetic materials have attracted the attention of several researchers in recent decades, mainly because of the exotic magnetic properties and superconductivity of some of these materials. One of these materials is KTb(WO 4 ) 2 , generally considered a prototype of the 2D Ising model. However, KTb(WO 4 ) 2 has some peculiarities in its magnetization behaviour under a magnetic field low-temperature regime. This peculiarity especially concerns the nonlinear dependence of magnetization to an applied magnetic field which is a behaviour that cannot be described using a pure two-dimensional Ising model. KTb(WO 4 ) 2 undergoes a metamagnetic phase transition at low temperatures, and we believe that such behaviour may be related to quantum effects and high magnetic anisotropy. Therefore, KTb(WO 4 ) 2 cannot be a perfect prototype for the 2D Ising model. In this work, we present a proposal to use the anisotropic quantum Heisenberg model to describe the magnetic properties of the KTb(WO 4 ) 2 quasi-doublet. Our main objective is to describe nonlinear magnetic properties at the low-temperature regime (T < 0.5 K). To achieve our objective, we simulate the magnetic properties of the material considering the anisotropy parameter Δ values via quantum Monte Carlo (QMC) and compare the results to published experimental data. For comparison, we plot diagrams of magnetization versus field and susceptibility as a T function of temperature. Our results show close agreement with the experimental data, especially at low temperatures and for intermediate values of the magnetic anisotropy parameter. [ABSTRACT FROM AUTHOR]

Low-dimensional magnetic materials have attracted the attention of several researchers in recent decades, mainly because of the exotic magnetic properties and superconductivity of some of these materials. One of these materials is KTb(WO 4 ) 2 , generally considered a prototype of the 2D Ising model. However, KTb(WO 4 ) 2 has some peculiarities in its magnetization behaviour under a magnetic field low-temperature regime. This peculiarity especially concerns the nonlinear dependence of magnetization to an applied magnetic field which is a behaviour that cannot be described using a pure two-dimensional Ising model. KTb(WO 4 ) 2 undergoes a metamagnetic phase transition at low temperatures, and we believe that such behaviour may be related to quantum effects and high magnetic anisotropy. Therefore, KTb(WO 4 ) 2 cannot be a perfect prototype for the 2D Ising model. In this work, we present a proposal to use the anisotropic quantum Heisenberg model to describe the magnetic properties of the KTb(WO 4 ) 2 quasi-doublet. Our main objective is to describe nonlinear magnetic properties at the low-temperature regime (T < 0.5 K). To achieve our objective, we simulate the magnetic properties of the material considering the anisotropy parameter Δ values via quantum Monte Carlo (QMC) and compare the results to published experimental data. For comparison, we plot diagrams of magnetization versus field and susceptibility as a T function of temperature. Our results show close agreement with the experimental data, especially at low temperatures and for intermediate values of the magnetic anisotropy parameter. [ABSTRACT FROM AUTHOR]

The Ba3InGa2O7.5 complex oxide, possessing the perovskite-related structure with structural oxygen vacancies, was first synthesized by the solid state method. The phase was found to be characterized by monoclinic symmetry (sp. gr. P2/c) with the following unit cell parameters: a = 7.942(1) Å, b = 5.868(5) Å, c = 18.201(6) Å, b = 91.52(9). Comprehensive investigations of electrical properties were carried out; ceramic material based on the complex oxide was shown to be a predominantly ionic conductor in the temperature range 450–900 oC. The conductivity is due to oxygen-ion transfer in dry conditions and oxygen-ion and proton transfer in wet atmosphere. The proton conductivity value is 4.5·10–5 S/cm, and the proton transport number is ~50% at 700 oC in wet air; at lower temperatures, proton transport becomes dominant. Prolonged treatment of the sample in water vapors below 450 oC leads to hydrolysis decomposition.

The paper reports the results of the study on the synthesis of new heterometallic complexes of Co(II) and Nd(III) with succinic acid in the presence of 1,10-phenanthroline or pyridine. The following hetero- and monocomplexes were synthesized: [Co(C4H4O4)-2Py]-2H2O and [Co(C4H4O4)- Phen].2H2О; [Nd,(C4H4O4)3]5H2О and [Nd(C4H4O4)3 2Phen]2H2O; [Co2Nd2(C4H4O4)54Py]4H2O and [Co2Nd2(C4H4O4)52Phen]4H2O (Phen - phenanthroline, and Py - pyridine). The study of their composition, structure, thermal properties and determination of the ability of he-terocomplexcs to form complex oxides was carried out. The complexes were characterized by a number of physicochemical methods: elemental analysis, IR- and diffuse reflection spectroscopies, X-ray powder diffraction and differential thermal analysis. Based on the analysis of diffuse reflection spectra and IR spectra ofhcterocomplexcs, it was shown that succinic add and 1,10-phenanthroline are bidentatcly bound to metal atoms. The metals arc connected by succinic acid, forming a chain. Oxide powders were obtained during thermolysis of hc-tcrocomplcxcs up to 00°C. The-composition of the synthesized hcteromctallic compounds was controlled by X-ray powder diffraction. It was shown that a complex oxide of NdCoO3 (cubic crystal system), without impurities, was formed, when the heterocomplex of phenanthroline [Co2Nd2(C4H4O4)3-2 Phen]-411,0 was heated to 800°C. When heating the heterocomplex of pyridine [Co2Nd2(C4H4O4)5-4Py]-4H2O, in addition to the complex oxide-NdCoO3, oxides Nd2O3 (hexagonal crystal system), Nd2O3 (cubic crystal system) and Co3O4 oxide-(cubic crystal system) were forme-d. The he-terocomplex [Co2Nd2(C4H4O4)5-2Phcn]-4H2O can be used as a precursor for the synthesis of cobaltate of neodymium with lower energy costs than in solid-phase synthesis. [ABSTRACT FROM AUTHOR]

In present study, Fe-22Cr-4.5Al oxide dispersion strengthened ferritic alloys were fabricated using a pre-alloyed powder with different minor alloying elements, and their microstructures and tensile properties were investigated to develop the advanced structural materials for high temperature service components. Planetary-typed mechanical alloying and uniaxial hot pressing processes were employed to fabricate the Fe-Cr-Al oxide dispersion strengthened ferritic alloys. Microstructural observation revealed that oxide dispersion strengthened ferritic alloys with Ti, Zr additions presented extremely fine micro-grains with a high number density of nano-scaled oxide particles which uniformly distributed in micro-grains and on the grain boundaries. These oxide particles were confirmed as a fine complex oxide, Y2Zr2O7. These favorable microstructures led to superior tensile properties than commercial ferritic stainless steel and oxide dispersion strengthened ferritic alloy with only Ti addition at elevated temperature.

The complex oxide Ba2InAlO5 was obtained by the solid-phase method. Its thermal and transport properties were studied for the first time while varying the temperature and composition of the gas phase (partial pressure of water and oxygen vapors). The possibility of dissociative incorporation of water in the structure of the complex oxide, leading to the formation of proton defects and proton transfer in the medium temperature range (500–700°C), was established. The conductivity was differentiated into components. It was proved that the total electric conductivity of the phase in dried air is mainly of hole type with a small contribution of oxygen-ion transport. In a humid atmosphere, the contribution and magnitude of ion conductivity increase due to the appearance of proton transfer. [ABSTRACT FROM AUTHOR]

The complex oxide Ba2InAlO5 was obtained by the solid-phase method. Its thermal and transport properties were studied for the first time while varying the temperature and composition of the gas phase (partial pressure of water and oxygen vapors). The possibility of dissociative incorporation of water in the structure of the complex oxide, leading to the formation of proton defects and proton transfer in the medium temperature range (500–700°C), was established. The conductivity was differentiated into components. It was proved that the total electric conductivity of the phase in dried air is mainly of hole type with a small contribution of oxygen-ion transport. In a humid atmosphere, the contribution and magnitude of ion conductivity increase due to the appearance of proton transfer. [ABSTRACT FROM AUTHOR]

Strontium and cobalt-free LaNi0.6Fe0.4O3–δ is considered one of the most promising electrodes for solid-state electrochemical devices. LaNi0.6Fe0.4O3–δ has high electrical conductivity, a suitable thermal expansion coefficient, satisfactory tolerance to chromium poisoning, and chemical compatibility with zirconia-based electrolytes. The disadvantage of LaNi0.6Fe0.4O3–δ is its low oxygen-ion conductivity. In order to increase the oxygen-ion conductivity, a complex oxide based on a doped ceria is added to the LaNi0.6Fe0.4O3–δ. However, this leads to a decrease in the conductivity of the electrode. In this case, a two-layer electrode with a functional composite layer and a collector layer with the addition of sintering additives should be used. In this study, the effect of sintering additives (Bi0.75Y0.25O2–δ and CuO) in the collector layer on the performance of LaNi0.6Fe0.4O3–δ-based highly active electrodes in contact with the most common solid-state membranes (Zr0.84Sc0.16O2–δ, Ce0.8Sm0.2O2–δ, La0.85Sr0.15Ga0.85Mg0.15O3–δ, La10(SiO4)6O3–δ, and BaCe0.89Gd0.1Cu0.01O3–δ) was investigated. It was shown that LaNi0.6Fe0.4O3–δ has good chemical compatibility with the abovementioned membranes. The best electrochemical activity (polarization resistance about 0.02 Ohm cm2 at 800 °C) was obtained for the electrode with 5 wt.% Bi0.75Y0.25O1.5 and 2 wt.% CuO in the collector layer.

Samples of general formula Ba0.9Ln0.1Fe1 –yCoyO3 – δ (Ln = Nd, Sm, Eu; y = 0.1–0.9) were studied at 1100°С under air. X-ray powder diffraction data for samples prepared by glycerol–nitrate technology were used to determine the homogeneity range of Ba0.9Ln0.1Fe1 –yCoyO3 – δ solid solutions (ss): 0.1 ≤ y ≤ 0.7 for Ln = Nd, 0.1 ≤ y ≤ 0.5 for Ln = Sm, and 0.1 ≤ y ≤ 0.4 for Ln = Eu. The crystal structure of single-phase oxides was described in terms of a cubic unit cell (space group ). The increasing cobalt content or rare-earth atomic radius brings about an increase in Ba0.9Ln0.1Fe1 –yCoyO3 – δ unit cell parameter. The oxygen content (3 – δ) in the temperature range 25–1100°C under air was determined by thermogravimetry and iodometric titration. Oxygen exchange between the solid oxide and gas phase starts at ~350°С. The oxygen content and mean oxidation state of the 3d metal in Ba0.9Ln0.1Fe1 –yCoyO3 – δ both decrease as the cobalt concentration increases or the lanthanide atomic number increases. [ABSTRACT FROM AUTHOR]

• New composite photocatalysts based on Bi 2 W 1-x Mo x O 6 (x = 0, 0.5, 1) powders deposited on a metal mesh and PMMA have been obtained. • A comparative study of their photocatalytic activity was carried out. • The mechanism of MB photooxidation has been studied, the main radical species have been identified. • A pathway for the decomposition of methylene blue has been proposed. New photocatalytic materials based on complex oxides and widely used and cheap carriers (stainless steel mesh and PMMA) have been prepared. The Bi 2 W 1-x Mo x O 6 (x = 0, 0.5, 1) powders were applied on the carrier surface using hydrothermal conditions and melting. The optimal way of the special pre-treatment for stainless steel mesh has been developed. The surface of the PMMA glass was softened to introduce powder particles into it. The morphology and elemental composition of materials were investigated by SEM with X-ray microanalysis. The photocatalytic activity was studied under visible light by methylene blue decomposition. All the obtained catalysts are characterized by the stability of the phase and elemental composition after photocatalysis. The differences in the mechanism of the photodecomposition process for all catalysts were studied experimentally using selective radical scavengers. The possible pathway of MB photooxidation was supposed by HR-LCMS analysis. [ABSTRACT FROM AUTHOR]

This work explores the effect of microstructure on the oxidation behavior of an equiatomic TaTiCr RCCA after 24 h of exposure at 800°C, 1000°C, 1200°C, and 1400°C. Two microstructural conditions, both containing a bcc matrix with C15 Laves precipitates, with one condition having coarser precipitates (∼10.9 µm diameter) and one condition having finer precipitates (∼2.9 µm diameter) were studied. At all oxidation temperatures except 800°C, the finer-scale (TaTiCr-F) condition experienced more rapid oxidation kinetics, higher mass gains, and thicker oxide scales and internal reaction zones. However, at 800°C, the microstructure containing coarser precipitates (TaTiCr-C) formed a thicker oxide scale. Continuous, protective Cr 2 O 3 layers were only observed in the coarse precipitate condition and correlations between Cr 2 O 3 layer thickness, subsequent formation of complex refractory oxides, and the initial Laves precipitate size are described. It is proposed that the formation of continuous Cr 2 O 3 is highly dependent on the size and distribution of the Cr-rich Laves phase and only mildly dependent on phase fraction. Oxidation mechanisms for each condition are discussed relative to the initial microstructures, observed oxide species, and related alloy systems. • Effects of precipitate size on oxidation kinetics, species, and morphologies were characterized. • Oxidation kinetics were accelerated in the fine precipitate condition temperatures above 800°C. • Precipitate size correlates directly with protective Cr 2 O 3 layer thickness and scale continuity. • (Cr,Ta,Ti)O 2 oxides are observed and Ta 2 O 5 is neutralized with the coarser precipitates. [ABSTRACT FROM AUTHOR]

Electron structure features of nanopowders with composition of (Na/K)VMoO 6 have been investigated both experimentally and theoretically. The dispositions of valence edge and conduction band were determined experimentally for vacuum condition by X-ray photoelectron spectroscopy, UV–visible and impedance spectroscopy and evaluated theoretically for water solutions. The additional absorbance band in the band gap has been found for both compounds, which leads to electron conductivity at low-temperature range (250–350 °C). Nanopowders have been prepared by sol-gel method with further ground in the planetary mill. Prepared powders in water solution have formed nanosuspension with size's particle up to 100 nm for NaVMoO 6 and 400 nm for KVMoO 6 , which is hardly sedimentated. The highly effective photocatalytic ability under visible light irradiation of the prepared compounds was observed using methylene blue decomposition process. The almost full methylene blue (20 mg/L) degradation is observed during 30 min for 10 mg of the photocatalysts. The investigation of possible dye degradation pathway has showed the high depth of decomposition. [Display omitted] • The (Na/K)VMoO 6 water nano suspensions have been prepared. • The electron structure of the compounds has been determined experimentally. • The high phototcatalytic activity of (Na/K)VMoO 6 under visible light has been found. • The active radical species generated by (Na/K)VMoO 6 has been investigated. • The MB decomposition products have been defined. [ABSTRACT FROM AUTHOR]

Iron-doped potassium titanate with a hollandite structure is synthesized by the solid-phase method. To reduce the contact resistance and to increase the diffusion coefficient of potassium ions, a conductive carbon coating is applied to the surface of the titanate synthesized in an argon atmosphere. The formation of the composite material is confirmed by the results of X-ray phase analysis, scanning electron microscopy, and IR spectroscopy. The half-cells with potassium metal in a CR2025 case, which are assembled on the basis of the synthesized composite, are tested electrochemically with subsequent calculation of the specific capacitance, power density, and energy density. It is found that the specific capacitance of an electrode with a carbon coating is 10–15% higher with low sweep rates (1 and 3 mV s–1). It is shown that the use of carbon coatings increases the diffusion coefficient of potassium to 1.77 × 10–14 cm2 s–1/2. [ABSTRACT FROM AUTHOR]

BaBiO3 is an oxide perovskite with a wide variety of interesting properties. It was expected that the compound would behave like a metal. However, experiments revealed that BaBiO3 is not metallic, which started an extensive debate about the mechanism responsible for this insulating behavior. The two most important conjectures in this debate are charge disproportionation of the Bi ion into 3+ and 5+ cations and bond hybridization of the Bi 6s and O 2p orbitals. Both mechanisms induce a breathing mode of the oxygen octahedra, which is experimentally observed in single crystals and thin films. Recently, ultra-thin BaBiO3 films were studied with the aim of suppressing the breathing mode, which was expected to result in re-emergence of metallicity. However, this expectation was not confirmed so far. Furthermore, theoretical calculations predict that BaBiO3 becomes a topological insulator (TI) when doped with electrons. Since high-temperature superconductivity was observed when doping the compound with holes, an interface between a superconductor and a TI can be established within the same parent compound. In this Review, we discuss the theoretical and experimental findings concerning the mechanism responsible for the unexpected insulating behavior of BaBiO3 for both single crystals and thin films. An overview is given of the current state of the art and the experimental challenges of achieving an oxide topological insulating state in BaBiO3.

LixLaySrzMnO3 thin films of various compositions (x,y,z) have been grown using pulsed laser deposition. The compositions of the films have been studied as a function of deposition temperature, target-to-substrate distance and deposition pressure with respect to different cation ratios of the targets by inductively coupled plasma mass spectrometry. When growing multi-elemental oxide thin films containing lithium (with its large mass difference to other elements), lithium loss is most probably inevitable. But the desired thin film composition can be achieved by selecting specific growth conditions and different target compositions. The experiments also elucidate some of the mechanisms behind the incongruent lithium transfer from the targets to thin films. [ABSTRACT FROM AUTHOR]

This study explores the oxidation behavior of a TaTiCr refractory complex concentrated alloy (RCCA) in the temperature regime of 800–1400 °C. The oxidation kinetics were found to be proportional with temperature. However, a mechanistic shift from linear oxidation kinetics at 800 °C and 1000 °C to sub-parabolic kinetics at 1200 °C and 1400 °C was observed. This was attributed to the establishment of continuous external scales of TiO 2 and Cr 2 O 3 , with fairly continuous underlying complex oxide layers at the higher temperatures. While there were morphological differences in the oxide scales depending on exposure temperature, the oxide species were all similar, primarily consisting of an outer layer of TiO 2 , an intermediate layer of Cr 2 O 3 , and an inner layer of rutile-structured (Cr,Ta,Ti)O 2. Internal nitridation was observed in all cases, with a severe degree of internal reaction at 1400 °C, reaching a depth of 750 μm. Overall, the best performance was observed at 1200 °C, where a favorable balance of kinetics and thermodynamics promoted the most continuous oxide layers, thereby enhancing oxidation resistance. • Oxidation kinetics and reaction products were characterized after 24 h at 800, 1000,1200, and 1400 °C for a TaTiCr RCCA. • Oxidation kinetics transition from near-linear at 800 °C and 1000 °C to sub-parabolic at 1200 °C and 1400 °C • The total reacted volume increased with temperature, however reaction product species remained similar across all temperatures. • Deleterious effects of Ta 2 O 5 are neutralized due to complex oxide formation (e.g. (Cr,Ta,Ti)O 2 and TaTiO 4). [ABSTRACT FROM AUTHOR]

Sm0.9Ca1.1Fe0.7Co0.3O4-δ oxide with the K2NiF4-type structure was prepared using a glycerin-nitrate technique. The XRD pattern of Sm0.9Ca1.1Fe0.7Co0.3O4-δ was refined by the Rietveld method within an orthorhombic structure (space group Bmab). The electrical conductivity, Seebeck coefficient, and thermal expansion of Sm0.9Ca1.1Fe0.7Co0.3O4-δ were measured depending on temperature in air. The change of oxygen nonstoichiometry determined by TGA in air does not exceed 0.01. The oxygen content in Sm0.9Ca1.1Fe0.7Co0.3O4-δ determined by the reduction in a hydrogen flux is equal to 3.96 ± 0.01. The positive value of Seebeck coefficient indicates that the predominant charge carriers in the oxide studied are electron holes.

The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.

Epitaxial PrBaCo2O5+δ (PBCO, 0≤ δ ≤ 1) thin films were deposited by pulsed laser deposition. The structural and electrical properties of the films were characterized at high temperatures in reduced environments. X-ray diffraction scans at high temperature in reduced environment show potential structural transitions of PBCO as evidenced by both a large (Δl = 0.335 nm) expansion of the out-plane (c-axis) lattice, due to thermal and chemical expansion, and a step in the expansion of the c-axis lattice parameter. These transitions indicate the presence of oxygen vacancy ordering as the oxygen content in the films is reduced. Resistivity measurements under the same environments also show evidence of sharp transitions related with the structural transformations. This study helps the understanding of the structure-property relationship of PBCO at high temperature and provides important technological information to utilize these materials for solid oxide fuel cell at intermediate temperatures.

The reduction of V2O5 to vanadium metal(0), that requires severe conditions in conventional reduction methods, was enabled to be proceeded in a short time of 1 h at 1273 K by the reaction with magnesium vapor with the isolation yield of V(0) in 55.6% by using microwave irradiation of 820 W. A pressurized pelletization of powdery V2O5 well‐mixed with MgO powder at a specific mixing ratio followed by calcination in ambient air at 1173 K was crucial for the reaction since a complex oxide of MgV2O4, presumably as a precursor, was formed in calcination of the V2O5/MgO pellet to be reduced to V(0) by the reaction with magnesium. Calcination of V2O5/MgO pellets with different mixing ratios or different temperatures resulted in the formation of different kinds of complex oxide of vanadium and magnesium such as α‐Mg2V2O7, Mg3(VO4)2, triclinic Mg2V2O7, and MgV2O6. While the yield of V(0) was dependent on the kind of the complex oxide, formation of MgV2O4 was essential as the precursor to the formation of V(0). [ABSTRACT FROM AUTHOR]

Processing of titanium-containing ores together with the extraction of all the major elements is currently an urgent problem for the usage of mineral products. It is shown that none of the existing processing schemes allows the simultaneous extraction of all the major useful elements such as iron, titanium and vanadium from titanium-containing iron ores. This problem can be solved using a selective extraction of these elements based on ideas regarding the electron reduction mechanism. The following has been experimentally studied: the reaction propagation of solid-phase selective iron reduction that is deep in the grain layer of ilmenite concentrate from the surface of its contact with the powder of carbon-containing material. The results are presented for determining the amount of released metal phase depending on the distance from the concentrate–reducing agent contact boundary. Based on the results regarding the amount of the released metal phase, a conclusion was made for the diffusion processes in a layer of concentrate grains that contact only between themselves, thus determining the rate of iron reduction process. It is shown that near the contact surface between the solid reducing agent and the layer of concentrate grains, the rate of iron reduction is higher than the formation rate of the phases with high iron content from ilmenite. Deep in the ilmenite concentrate layer, the process of iron reduction is preceded by the formation of an iron-containing silicate phase from the concentrate grains, where iron is reduced earlier than it is in the ilmenite grains. The formation of iron-containing silicate phase promotes ilmenite grains to be sintered. Thus, upon the concentrate layer contacting with solid reducing agent in the absence of contact between each ilmenite grain and solid reducing agent, the point contact between grains and void presence within the layer do not prevent the reduction process propagation in the grain layer that contact only with each other. [ABSTRACT FROM AUTHOR]

The rheological behavior of electrorheological fluids with dispersed fillers whose particles have different crystalline structures is investigated in direct and alternating electric fields. The dielectric characteristics of the materials were measured and the influence of the strength, frequency, and shape of the signal of electric field was investigated, and the influence of temperature on the shear stress in electrorheological fluids was estimated in direct current electric field. [ABSTRACT FROM AUTHOR]

Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1- x)BiTi(1- y)/2Fe y Mg(1- y)/2O3–(x)CaTiO3 (BTFM–CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 μB/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7–3.0 × 10−7 s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM–CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications. [ABSTRACT FROM AUTHOR]

The material BaBiO3 is known for its insulating character. However, for thin films, in the ultra-thin limit, metallicity is expected because the oxygen octahedra breathing mode will be suppressed as reported recently. Here, we confirm the influence of the oxygen breathing mode on the size of the band gap. The electronic properties of a BaBiO3 thickness series are studied using in-situ scanning tunneling microscopy. We observe a wide-gap (EG > 1.2 V) to small-gap (EG ≈ 0.07 eV) semiconductor transition as a function of a decreasing BaBiO3 film thickness. However, even for an ultra-thin BaBiO3 film, no metallic state is present. The dependence of the band gap size is found to be coinciding with the intensity of the Raman response of the breathing phonon mode as a function of thickness.

Abstract The modification of the discharge area in flat panel plasma discharge devices having a complex metal oxide protective layer on prolonged aging was demonstrated. In the case of a (Mg,Ca)O protective layer, the discharge area shrank with the discharge intensity reduced during aging. The CaO concentration was increased at the layer surface by the preferential sputtering of MgO, which is promoted by higher Xe levels in the discharge gas. These results indicate that a modified distribution of the secondary electron emission property at the surface due to the compositional change leads to the shrinkage of the discharge area. This work also demonstrated that reducing the permittivity of the dielectric layer under the protective layer expanded the discharge area, thus suppressing the degradation of the discharge intensity in the plasma discharge devices. Highlights • Shrinkage of discharge areas appears with a complex metal oxide protective layer. • Preferential sputtering during aging modifies the composition at the layer surface. • A distribution of properties due to compositional changes results in the shrinkage. • More Xe in the discharge gas enhances the preferential sputtering of MgO. • Adjusting the dielectric layer properties enables the discharge area to be widened. [ABSTRACT FROM AUTHOR]

Abstract Y 2 O 3 is mainly applied as a dispersoid in Ni-based oxide dispersion strengthened (ODS) alloys. The added Y 2 O 3 reacts with Ti and Al at a temperature above 1150 ℃ to form a complex oxide such as Y-Ti-O or Y-Al-O complex oxide. However, previous studies have shown that Y-Al-O complex oxide has relatively coarser particles than Y-Ti-O complex oxide. In this study, Ti was first added to form Y-Ti-O complex oxide, which has relatively fine particles. Subsequently, Al was added to inhibit the formation of Y-Al-O complex oxide, thus improving the high-temperature mechanical properties of ODS alloys. Ni-based ODS alloy powders with composition Ni-15Cr-xTi-1.1Y 2 O 3 (without aluminum) were mechanically alloyed using a planetary mill. Thereafter, the mechanically alloyed powders were heat treated to form a complex oxide of Y-Ti-O. A second mechanical alloying was performed by adding 4.5 wt% Al to the heat treated powders. The products obtained after the second alloying were sintered by spark plasma sintering. The phase of the sintered specimens were analyzed using X-ray diffraction, their microstructures were analyzed by transmission electron microscopy and the size distribution of oxide particles was confirmed by image analysis. Moreover, the high-temperature mechanical properties of each composition were analyzed using a hot hardness tester. [ABSTRACT FROM AUTHOR]

Cesium-containing complex oxides Cs[MgR0.5P1.5O6], where R = B, Al, or Fe, were prepared from solutions containing H3BO3, metal nitrates, and H3PO4/NH4H2PO4. The chemical and phase transformations occurring during the synthesis of these oxides were elucidated by differential thermal analysis (DTA) and X-ray powder diffraction (XRD. Optimal synthesis parameters were found. The boron compound was found to be formed at 800°C, and the aluminum and iron compounds, at 1200°C. All compounds have the pollucite structure (cubic system, space group I4132). A comparative analysis of the synthesis of complex oxides under study from various precursors that differed from one another in metal and phosphorus chemical species was carried out. [ABSTRACT FROM AUTHOR]

Photocatalysts are the most important technology in air pollution removal and the detoxification of organic materials. Doping and complexation are among the most used methods to improve the efficiency of photocatalysts. Titanium dioxide and zinc oxide nanomaterials are widely used materials for photocatalysts and the degradation of toxic materials. Their mixed structure can be fabricated by many methods and the structure affects their properties. Nanofibers are efficient materials for photocatalysts due to their vertically formed structure, which improves the charge separation of photoelectrons. We fabricated them by an electrospinning process. A precursor consisting of titanium 4-isopropoxide, zinc acetate dihydrate and polyvinylpyrrolidone was used as a spinning solution for a mixed structure of titanium dioxide and zinc oxide with different molar ratios. They were then calcined, crystallized by heat treatment and analyzed by thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM) and energy-dispersive spectroscope (EDS). After annealing, the average diameters of the Ti–Zn complex oxide nanofibers were 237.6–278.6 nm with different salt ratios, and multiple crystalline structures were observed, namely TiO2, ZnO, ZnTiO3 and Zn2TiO4. We observed the photocatalytic performance of the samples and compared them according to the photodegradation of methylene blue. The methylene blue concentration decreased to 0.008–0.650 after three hours, compared to an initial concentration of 1, with different metal oxide structures.

Oxide dispersion-strengthened (ODS) materials contain homogeneous dispersions of temperature-stable nano-oxides serving as obstacles for dislocations and further pinning of grain boundaries. The strategy for dispersion strengthening based on complex oxides (Y-Hf, -Zr, -Ce, -La) was developed in order to refine oxide dispersion to enhance the dispersion strengthening effect. In this work, the strengthening of EUROFER steel by complex oxides based on Y and elements of the IIIB group (lanthanum, scandium) and IVB group (cerium, hafnium, zirconium) was explored. Interparticle spacing as a dispersoid characteristic appeared to be an important factor in controlling the dispersion strengthening contribution to the yield strength of ODS EUROFER steels. The dispersoid size and average grain size of ODS EUROFER steel were altered in the ranges of 5−13 nm and 0.6−1.7 µm, respectively. Using this strategy, the yield strength of the prepared alloys varied between 550 MPa and 950 MPa depending on the doping element.

Double perovskite Sr 2 Ni 0.75 Mg 0.25 MoO 6-δ powders were synthesized by the combustion method using systems containing nitrates and varying amounts of the following organic components: glycine, glycerol, and polyvinyl alcohol. The characteristics (temperature, gas composition, etc.) of the synthesis process were studied and the optimal conditions for obtaining single-phase samples were determined. It was established that the usage of one-and-a-half excess of glycerol as organic component provides the formation single-phase complex oxide. The crystal structure of the obtained complex oxide, which is of interest as an anode material for solid oxide fuel cells, was refined and its physico-chemical properties (specific surface area, particle size, electrical conductivity, and catalytic activity in the reaction of methane oxidation) were investigated. [ABSTRACT FROM AUTHOR]