49 results on '"Elizaveta V. Shalaeva"'
Search Results
2. Novel testing procedure of area-specific exchange current density for photoactive powder: Application in PEC water splitting
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Vladimir Yu. Kolosov, E.S. Ulyanova, Elizaveta V. Shalaeva, Olga I. Gyrdasova, Boris T. Tarasanov, Vladimir N. Krasil’nikov, A. A. Yushkov, and S. N. Shkerin
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Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,Exchange current density ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electrochemical cell ,Fuel Technology ,Chemical engineering ,Electrode ,Photocatalysis ,Water splitting ,0210 nano-technology ,Polarization (electrochemistry) ,Visible spectrum - Abstract
The study reports a novel patented test and the electrochemical cell for its implementation to estimate the area-specific exchange current density for photoactive powder. The test was employed for the photo-electrode reaction in the PEC water splitting. Testing procedure included impedance measurements and was carried out in the original three-electrode cell with an alkaline electrolyte where working Ni electrode behaves as an ideal polarized electrode and is in immediate contact with the photoactive powder additive. The application of this test is presented for the UV- and visible light photoactive TiO2-xCx:nC powder. The test of TiO2-xCx:nC powder confirmed that the polarization resistance of the designed electrochemical cell is due only to photoactive powder. The area-specific exchange current density was determined for the photo-electrode reactions on TiO2-xCx:nC powder under UV- and visible light, as well as their ratio. The obtained ratio correlates well with the previous data on the rate constants for the UV- and visible-driven photocatalytic oxidation of a model solution performed in the presence of the same powder TiO2-xCx:nC. more...
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- 2021
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3. Study of structural, spectroscopic and photo-oxidation properties of in-situ synthesized Sc-doped titania
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L. A. Pasechnik, Andrei N. Enyashin, A. A. Yushkov, M. Yu. Yanchenko, Elizaveta V. Shalaeva, N. S. Kozhevnikova, M. V. Kuznetsov, A. S. Vorokh, E.S. Ulyanova, L. Yu. Buldakova, A. O. Bokunyaeva, and Tatyana I. Gorbunova more...
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Anatase ,Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,X-ray photoelectron spectroscopy ,Materials Chemistry ,Scandium ,Physical and Theoretical Chemistry ,High-resolution transmission electron microscopy ,Spectroscopy ,Brookite ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,chemistry ,visual_art ,visual_art.visual_art_medium ,Photocatalysis ,Physical chemistry ,0210 nano-technology ,Titanium - Abstract
A semiconducting composite with enhanced photocatalytic properties – scandium doped titania (anatase/amorphous titania/brookite) – was prepared by hydrolysis of titanium (IV) tetrabutoxide in the presence of scandium (III) sulfate aqueous solution. The characterization of the final products was accomplished through X-ray diffraction (XRD), scanning and high resolution transmission electron microscopy (SEM, HRTEM), UV–visible spectroscopy (UV–Vis), X-ray photoelectron spectroscopy (XPS) and by registration of photocatalytic activity during photo oxidation of aromatic organic compound (hydroquinone). The Sc-doped powder-like product is a mixture of anatase/brookite or anatase/brookite/amorphous nanoparticles. The effects of Sc-doping on the phase composition, optical properties and photoactivity of TiO2 were investigated. The XRD analysis confirmed the absence of individual Sc-containing compounds. The phase composition and particle size of TiO2 were characterized by the Debye analysis of X-ray diffraction patterns. A direct correlation between Sc concentration and TiO2 phase composition was established: increasing in Sc concentration promotes amorphization of the samples. DFT calculations distinguish both brookite and amorphous titania among all TiO2 polymorphs as the most preferred hosts for substitutional Sc atoms. In full accordance with TEM observations the possible inclusion of Sc into a TiO2 lattice is primarily gainful for amorphization. Both experimental and theoretical absorbance spectra for amorphous titania demonstrate a shift of absorbance onset towards larger wavelengths. An improvement in the catalyst's photodegradation efficiency was attained with Sc concentration of 5.0 mol%. more...
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- 2019
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4. Low-Temperature Sol–Gel Synthesis and Photoactivity of Nanocrystalline TiO2 with the Anatase/Brookite Structure and an Amorphous Component
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L. Yu. Buldakova, M. Yu. Yanchenko, A. S. Vorokh, A. O. Bokunyaeva, A. A. Yushkov, Elizaveta V. Shalaeva, Marina G. Pervova, Andrei N. Enyashin, N. S. Kozhevnikova, D. A. Zamyatin, Tatyana I. Gorbunova, E.S. Ulyanova, and V. Yu. Kolosov more...
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Anatase ,010405 organic chemistry ,Brookite ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,Nanocrystalline material ,0104 chemical sciences ,Computer Science Applications ,Amorphous solid ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Rutile ,Modeling and Simulation ,visual_art ,Titanium dioxide ,visual_art.visual_art_medium ,Photocatalysis ,Titanium - Abstract
Nanodispersed TiO2 consisting of anatase and brookite phases in a ratio of 3 : 1 is obtained by the sol–gel method from titanium(IV) butoxide at a temperature below 100°C. X-ray diffraction, transmission electron microscopy, and Raman spectroscopy are used to show that the size of anatase particles is about 6 nm, and brookite particles consist of a crystal core, 4 nm in diameter, surrounded by an amorphous shell. Compared with the commercial Degussa P25 photocatalyst, which consists of the anatase and rutile phases in the same 3 : 1 ratio, the resulting TiO2 exhibits an increased photoactivity in hydroquinone oxidation. Quantum chemical modeling of anatase and brookite surfaces as well as their interface does not reveal the specific features of their electronic structure. This fact is indicative of the amorphous phase as an active participant in the transfer of charge carriers in the photocatalytic process. more...
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- 2019
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5. Structural features and high-temperature transport in SrFe0.7Mo0.3O3−
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Alexey A. Markov, Elizaveta V. Shalaeva, I. A. Leonidov, V.L. Kozhevnikov, Mikhail V. Patrakeev, O.V. Merkulov, and Alexander P. Tyutyunnik
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Electron mobility ,Materials science ,Annealing (metallurgy) ,Inorganic chemistry ,Oxide ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Oxygen ,Inorganic Chemistry ,chemistry.chemical_compound ,Electrical resistivity and conductivity ,Materials Chemistry ,Physical and Theoretical Chemistry ,Partial pressure ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,chemistry ,Electron diffraction ,Ceramics and Composites ,Water splitting ,0210 nano-technology - Abstract
The complex oxide SrFe0.7Mo0.3O3−δ was obtained by combustion of the organometallic precursor in air followed by annealing in an argon flow at 1350 °C, and characterized with the help of X-ray and electron diffraction methods. Oxygen nonstoichiometry and electrical conductivity data were collected in the oxygen partial pressure range from 10–19 to 0.5 atm at temperatures 750–950 °C. The as-prepared single phase oxide SrFe0.7Mo0.3O3−δ with the cubic double perovskite structure (SG Fm3m) is shown to undergo a structural transition to the tetragonal double perovskite phase (SG I4mmm) in the result of reducing treatment at p O 2 = 10−12 atm and 950 °C. The ordered phases are characterized by a strong anti-site disordering of iron and molybdenum and nearly zero long-range ordering parameter. The maximal concentration of n-type carriers is about four times larger than of p-type carriers in the studied limits of oxygen pressure and temperature. The mobility of p-type carriers is found to vary within ~ 0.02–0.03 cm2 V−1 s−1 with the migration energy of about 0.4 eV, while the n-type mobility being approximately twice higher does not practically depend on temperature. Such features as good electrical conductivity, which can rise up to 40 S cm−1 in reducing conditions and a considerable amount of oxygen vacancies favorable for fast oxygen ion transport are beneficial for application of SrFe0.7Mo0.3O3−δ as anode material in SOFCs and oxygen membrane for hydrogen generation by a water splitting. more...
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- 2018
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6. Effect of Cu+ ions on the structure, morphology, optical and photocatalytic properties of nanostructured ZnO
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Elizaveta V. Shalaeva, Мikhail Yu. Yanchenko, Оlga I. Gyrdasova, Мikhail V. Kuznetsov, Vladimir N. Krasil’nikov, Larisa Yu. Buldakova, M. A. Melkozerova, and Inna V. Baklanova
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Materials science ,Morphology (linguistics) ,Mechanical Engineering ,Thermal decomposition ,chemistry.chemical_element ,Condensed Matter Physics ,Copper ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Mechanics of Materials ,Photocatalysis ,General Materials Science ,Hybrid material ,Ethylene glycol ,Solid solution - Abstract
Solid solutions Zn1−xCuxO and/or hybrid materials Zn1−xCuxO/CuxO of the “core-shell” type were obtained by one-step thermolysis of Zn1−хCux(HCOO)(OCH2CH2O)1/2 complexes. Precursors the Zn1−хCux(HCOO)(OCH2CH2O)1/2 complexes were synthesized under solvothermal method from the corresponding formates and ethylene glycol. It was established that copper in these materials is a promoter of the photoactivity and morphology of aggregates. Zn1−xCuxO solid solutions (0 O2−. more...
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- 2021
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7. The impact of cerium content on oxygen stoichiometry, defect equilibrium, and thermodynamic quantities of Sr1−Ce FeO3−
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B.V. Politov, Alexey A. Markov, I. A. Leonidov, Elizaveta V. Shalaeva, Mikhail V. Patrakeev, Alexander P. Tyutyunnik, and S.S. Nikitin
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Steric effects ,Strontium ,Materials science ,Ionic radius ,Mechanical Engineering ,Metals and Alloys ,chemistry.chemical_element ,Thermodynamics ,02 engineering and technology ,Partial pressure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Oxygen ,0104 chemical sciences ,Ion ,Cerium ,chemistry ,Electron diffraction ,Mechanics of Materials ,Materials Chemistry ,0210 nano-technology - Abstract
The structure, oxygen non-stoichiometry, and defect equilibrium in perovskite-type Sr1−xCexFeO3−δ (x = 0.05, 0.10, 0.15, 0.20) were studied. X-ray diffraction showed the formation of a cubic structure for all compositions. The electron diffraction detected an incommensurate structure with a modulation wave vector 0.41 a* in compositions with x ≥ 0.10. The phenomenon is assumed to originate from a strong steric disturbance attributed to a large difference in ionic radii of cerium and strontium. The data on the oxygen content acquired in wide ranges of oxygen partial pressure and temperature were used for the modeling of defect equilibrium in oxides. A part of anion vacancies in Sr1−xCexFeO3−δ was found to be inaccessible for oxygen ions. The main factors of cerium substitution impact on the thermodynamic parameters of defect formation reactions in Sr1−xCexFeO3−δ were revealed to be lattice contraction, steric disturbance, and cerium reduction to Ce3+. The concentration of Ce3+ ions in Sr1−xCexFeO3−δ under reducing conditions was found to be substantially greater than that of Fe2+. Interrelations between thermodynamic quantities of oxygen in Sr1−xCexFeO3−δ and thermodynamic parameters of defect formation reactions were considered. more...
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- 2021
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8. PHOTO-CATALYSTS ON THE BASIS OF QUASI-UNIDIMENSIONAL STATE OF COBALT AND COPPER ACTIVATED
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M. A. Melkozerova, Inna V. Baklanova, Olga I. Gyrdasova, Elizaveta V. Shalaeva, Natalya S. Sycheva, and L. Yu. Buldakova
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Materials science ,synthesis ,Basis (linear algebra) ,dynamics of electron excitations ,microstructure ,Inorganic chemistry ,lcsh:QD450-801 ,defects of structure ,chemistry.chemical_element ,lcsh:Physical and theoretical chemistry ,State (functional analysis) ,Copper ,Catalysis ,photocatalysts ,chemistry ,Zinc oxide ,nanostructures ,morphology ,precursors ,Cobalt - Abstract
Zn1-xMxO (0 ≤ x ≤ 0,1) solid solutions with tubular morphology of aggregates and Zn1-xMxO1-yCy : nMO (0,1 ≤ x ≤ 0,3) composites were obtained using formate-glycolate complexes Zn1-xMx(HCOO)(OCH2CH2O)1/2 (M = Co, Cu; 0 ≤ x ≤ 0,3). The materials are tested in the oxidation of 1,4-dihydroxybenzene under the action of visible radiation. It is established that copper in Zn1-xMxO (0 ≤ x ≤ 0,1) is more effective than cobalt. Its presence in composites leads to a decrease of the photocatalytic activity. more...
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- 2017
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9. Fe and C doped TiO2 with different aggregate architecture: Synthesis, optical, spectral and photocatalytic properties, first-principle calculation
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Vladlen P. Zhukov, Inna V. Baklanova, E. V. Polyakov, Elizaveta V. Shalaeva, E. G. Vovkotrub, M. V. Kuznetsov, Olga I. Gyrdasova, L. Yu. Buldakova, I. R. Shein, and Vladimir N. Krasil’nikov
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Anatase ,Materials science ,Absorption spectroscopy ,Dopant ,Scanning electron microscope ,Doping ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,medicine.disease_cause ,01 natural sciences ,0104 chemical sciences ,X-ray photoelectron spectroscopy ,Photocatalysis ,medicine ,General Materials Science ,0210 nano-technology ,Ultraviolet - Abstract
Iron and carbon doped nanostructured titanium dioxide with different morphology of aggregates was synthesized using the developed precursor technique. Glycolate of the general composition Ti1-xFex(OCH2CH2O)2-x/2 (0 ≤ x ≤ 0.1) was used as a precursor. The synthesized samples of the compositions Ti1-xFexO2, Ti1-xFexO(2-x/2)-yCy and Ti1-xFexO(2-x/2)-yCy:nC were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet and visible absorption spectroscopy, as well as by vibration and X-ray photoelectron spectroscopy methods. In addition, they were tested as photocatalysts in the hydroquinone oxidation reaction under ultraviolet and visible irradiation. It is established that the insertion of iron into the structure of carbon-doped anatase (TiO2-yCy) suppresses its photocatalytic activity in the visible range of the spectrum, but leads to no change under ultraviolet irradiation. Globular samples of Ti1-xFexO(2-x/2)-yCy containing no more than 2.5 at% Fe show the maximum photocatalytic activity. To clarify the reasons for the observed complex dependence of photocatalytic activity on the concentration of the dopant first-principles, calculations of the electronic band structure and optical absorption of anatase doped with iron and carbon are performed and discussed. more...
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- 2017
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10. One-pot inorganic route to highly stable water-dispersible Ag 2 S quantum dots
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Alexander P. Tyutyunnik, Inna V. Baklanova, Elizaveta V. Shalaeva, Andrei S. Vorokh, A. A. Yushkov, Vladimir G. Zubkov, Vladimir Yu. Kolosov, and N. S. Kozhevnikova
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Aqueous solution ,Chemistry ,Mechanical Engineering ,Inorganic chemistry ,Metals and Alloys ,Ionic bonding ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Colloid ,Dynamic light scattering ,Mechanics of Materials ,Quantum dot ,Transmission electron microscopy ,Scanning transmission electron microscopy ,Materials Chemistry ,Molecule ,0210 nano-technology - Abstract
Direct aqueous synthesis of Ag2S QDs is a challenge because hydrophobic Ag2S QDs tend to aggregate to form large polycrystals. In this article, the low temperature one-pot route for obtaining highly stable aqueous colloid solutions of Ag2S QDs, using NH3 molecules as monodentate ligands, is reported. Ionic forms of all the species in solution including free ligand, free and complex silver ions, and free sulfide ions at any given experimental pH were calculated. The obtained speciation diagrams were necessary to determine synthetic parameters such as concentration ratios [Ag+]/[HS−] and [NH3]/[Ag+], and pH. The comprehensive investigation of Ag2S QDs' colloid solutions was carried out by high-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy (STEM), UV–vis–NIR spectroscopy, dynamic light scattering. The Ag2S QDs possessed monoclinic (acanthite) crystalline structure with an average size about 33 nm. Estimations of hydrodynamic diameter and degree of double layer charge in colloid solutions, i.e. the ς-potential measurements, proved high stability of colloidal system of Ag2S QDs on the order of several months under ambient conditions. Combination of both electrostatic and steric stabilization mechanisms kept Ag2S QDs uniformly dispersed in aqueous medium, with NH3 molecules playing a crucial role in avoiding aggregation of as-prepared Ag2S QDs. Colloid Ag2S QDs exhibited NIR emission at 1280 nm under 808 nm excitation. more...
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- 2017
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11. Facile, rapid and efficient doping of amorphous TiO 2 by pre-synthesized colloidal CdS quantum dots
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Larisa Yu. Buldakova, Mikhail Yu. Yanchenko, A.M. Murzakaev, N. S. Kozhevnikova, Olga I. Gyrdasova, Inna V. Baklanova, Elizaveta V. Shalaeva, Andrey N. Enyashin, Tatyana I. Gorbunova, and A. S. Vorokh more...
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Materials science ,Band gap ,Mechanical Engineering ,Doping ,Metals and Alloys ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Amorphous solid ,Crystal ,Crystallinity ,Chemical engineering ,Mechanics of Materials ,law ,Quantum dot ,Materials Chemistry ,Photocatalysis ,Crystallization ,0210 nano-technology - Abstract
Various methods have been developed to reduce the band gap of TiO2 via combining TiO2 with quantum dots (QDs). However, the attainment of high activity and stability of hybrid QDs/TiO2 is still a significant challenge since the poor interface contact between QDs and TiO2. This drawback could be tackled to some extent through optimisation of the preparation technology. The present study suggests a simple hydrolysis route to in situ TiO2 doping by pre-synthesized CdS QDs, which play a role of crystal seeds, pre-planted in liquid titanium alkoxide, for the TiO2 crystallization process. The comprehensive investigation of the CdS/TiO2 composite is carried out by X-ray diffraction, UV–Visible spectroscopy, scanning electron microscopy, photocatalytic activity measurements in the photo oxidation of cyclic aromatic organic compounds. The stability of model TiO2-shell structures on CdS seeds is assessed by means of molecular dynamics simulations. Both experimental and theoretical results confirm the mutual impact of CdS QDs and TiO2 on their crystallinity. The presence of CdS QDs in the solution provokes the formation of amorphous TiO2 clusters, while the high TiO2 content leads to amorphization of CdS QDs. The CdS/TiO2 composite particles consisting of CdS amorphous core and TiO2 amorphous shell demonstrate the highest photocatalytic activity. more...
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- 2017
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12. Visible light photoluminescence in TiO2/CdS nanopowders synthesized by sol-gel route: Effect of gel aging time
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V. Yu. Kolosov, Elizaveta V. Shalaeva, E.S. Ulyanova, and D. A. Zamyatin
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Anatase ,Materials science ,Photoluminescence ,Physics and Astronomy (miscellaneous) ,Materials Science (miscellaneous) ,Nanoparticle ,TIO2/CDS COMPOSITES ,Condensed Matter Physics ,symbols.namesake ,Mathematics (miscellaneous) ,Chemical engineering ,SOL-GEL ROUTE ,Rutile ,symbols ,NANOPARTICLES ,PHOTOLUMINESCENCE ,Raman spectroscopy ,DEFECT STATES ,Visible spectrum ,Sol-gel - Abstract
A series of sol-gel TiO2/CdS, TiO2 powders and coagulated CdS nanoparticles were studied by XRD, HRTEM and Raman spectroscopy to elucidate the effect of low-temperature gel aging time on visible photoluminescence (PL) emission of the TiO2/CdS composites. With an increase in aging time a content of amorphous titania and incorporated CdS nanoparticles decreases in composites. For all composites, visible PL emission includes bands attributed to surface oxygen vacancies and hydroxyl group of TiO2 nanocrystals, as well as yellow-green and red bands related to lattice defect states of CdS nanoparticles. It was found that gel aging time is a crucial parameter to influence visible PL emission in composites. This emission is suppressed with increasing aging time, and its evolution shows that healing of oxygen vacancy defects and hydroxyl group affect visible emission more significantly than improving crystallinity degree. The correlation between visible PL emission in TiO2/CdS and their visible-light photocatalytic activity was discussed. © 2020, ITMO University. All rights reserved. The research was carried out in accordance with the state assignment for ISSC UB RAS and financial support from ISSC UB RAS (theme AAAA-A19-119031890025-9). TEM study was supported by RFBR (grant No. 20-02-00906). The authors are grateful to Dr. Kozhevnikova N. S. and Dr. Gorbunova T. I. for the provided samples TiO2/CdS and CdS. more...
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- 2020
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13. Non-uniform electron conduction in weakly ordered SrFe
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Oleg V, Merkulov, Alexey A, Markov, Eugene N, Naumovich, Elizaveta V, Shalaeva, Ilia A, Leonidov, and Mikhail V, Patrakeev
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The electrical conductivity of SrFe1-xMoxO3-δ (0.07, 0.15, 0.25) was measured in the range of oxygen partial pressure of 10-16-0.5 atm and at temperatures 800-950 °C by a four-probe dc technique. Experimental results were satisfactorily simulated with a model suggesting that oxygen ions and electronic charge carriers of n- and p-types were involved in conduction. The mobility of charge carriers was calculated using partial conductivities and earlier published oxygen nonstoichiometry data. The mobility of p-type charge carriers was found to decrease in response to a decreasing oxygen content or an increasing molybdenum content in the oxide. The mobility of n-type carriers was found to be unaffected by the oxygen content, but exhibited an accelerating increase upon increasing the molybdenum content. Such behavior of the electron mobility was interpreted in view of the tendency of iron and molybdenum cations to undergo ordering based on the supposition that two different mechanisms of electron transport were involved in these oxides. It was assumed that nanoscale ordered areas with fast electron transport dispersed in the disordered perovskite matrix played the role of a high-conductivity filler in a composite consisting of two components with different conductivities. The behavior of the effective electron mobility was approximated well using the percolation theory. The molybdenum content x = 0.327 was calculated to be the percolation threshold in SrFe1-xMoxO3-δ. more...
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- 2019
14. MoO2/C composites prepared by tartaric acid and glucose-assisted sol-gel processes as anode materials for lithium-ion batteries
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E. Thauer, Rüdiger Klingeler, Quanyao Zhu, Z. A. Fattakhova, Galina S. Zakharova, Elizaveta V. Shalaeva, S. A. Wegener, and L. Singer
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Materials science ,FOS: Physical sciences ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,chemistry.chemical_compound ,Crystallinity ,Materials Chemistry ,Composite material ,Sol-gel ,Condensed Matter - Materials Science ,Mechanical Engineering ,Metals and Alloys ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Grain size ,0104 chemical sciences ,Anode ,chemistry ,Mechanics of Materials ,Tartaric acid ,Lithium ,0210 nano-technology ,Carbon - Abstract
MoO2/C-composites have been fabricated for the first time by a tartaric acid/glucose-assisted sol-gel method with post-annealing at 500 °C for 1 h in N2 flow. The synthesized materials were fully characterized with respect to structure, morphology, and electrochemical properties. Compared with tartaric acid-assisted products, the adoption of glucose as carbon source effectively increases the carbon content in the composites. Irrespective of the organic component, the composites exhibit low crystallinity and small grain size. This results in good electrochemical performance of the anode materials as confirmed for the glucose-assisted materials which after additional post treatment delivers a competitive electrochemical capacity. more...
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- 2021
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15. Pressure-induced zircon to monazite phase transition in Y1–х La х PO4: First-principles calculations
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I. R. Shein and Elizaveta V. Shalaeva
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Phase transition ,Materials science ,chemistry.chemical_element ,Mineralogy ,Thermodynamics ,02 engineering and technology ,Yttrium ,021001 nanoscience & nanotechnology ,01 natural sciences ,Inorganic Chemistry ,chemistry ,Phase (matter) ,Monazite ,0103 physical sciences ,Materials Chemistry ,Lanthanum ,Physical and Theoretical Chemistry ,010306 general physics ,0210 nano-technology ,Anisotropy ,Elastic modulus ,Zircon - Abstract
Density functional theory was used to study pressure-induced phase transitions of zircon to monazite in doped yttrium orthophosphate, Y1–хLaхPO4, for х = 0, 0.0625, 0.125. The pressures of the phase transition, the elastic moduli and the universal elastic anisotropy index were calculated. It was shown that with increasing lanthanum concentration in Y1–xLaxPO4, the transition pressure increases. According to the Birch–Murnaghan equation of state, this effect is associated with a decrease in the critical volume. The increased stability of the doped zircon phase compared to YPO4 is attributed to the more significant increase in the anisotropy and distortions of REO8 polyhedra and RE–O–P chains found for the optimized structures at critical volumes. more...
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- 2016
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16. Synthesis, structure and spectroscopic characteristics of Ti(O,C)2/carbon nanostructured globules with visible light photocatalytic activity
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Vladimir N. Krasil’nikov, A.M. Murzakaev, Olga I. Gyrdasova, L. Yu. Buldakova, E. V. Zabolotskaya, M. V. Kuznetsov, Elizaveta V. Shalaeva, M. A. Melkozerova, and Inna V. Baklanova
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Anatase ,Materials science ,Absorption spectroscopy ,Inorganic chemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Amorphous carbon ,X-ray photoelectron spectroscopy ,Chemical engineering ,chemistry ,Mechanics of Materials ,Transmission electron microscopy ,Titanium dioxide ,Photocatalysis ,General Materials Science ,0210 nano-technology ,Spectroscopy - Abstract
A morphology-controlled facile synthesis of titanium-glycolate precursors with subsequent annealing in He and air atmospheres has been exploited for the production of nanostructured composite globules, whiskers and plates of C-modified titanium dioxide. Characterisation tests proved the as-obtained globule composites to exclusively exhibit high-specific surface area (up to 150–170 m2 g−1), thus being useful for photocatalytic applications in the visible-light region. The combination of the electron paramagnetic resonance, X-ray photoelectron spectroscopy, absorption spectroscopy and transmission electron microscopy revealed the presence of three kinds of carbon in the globules: a small bandgap (with measured width of 0.8 eV) amorphous carbon surrounding the anatase nanocrystallites, C-containing radicals including carbonates on the surface of TiO2 and interstitial carbon in the oxygen position of the TiO2 lattice. It was found that the maximum visible-light photocatalytic activity of the globules is determined by the optimal surface concentration of amorphous carbon of about 0.002 wt.% m−2. Under these conditions, the highest synergic photosensitising effect on TiO2 nanocrystallites of all three kinds of carbon is expected. more...
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- 2016
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17. Local environment of CdS nanoparticles incorporated into anatase/brookite matrix via sol-gel route: HRTEM, Raman spectroscopy and MD simulation
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N. S. Kozhevnikova, Elizaveta V. Shalaeva, D. A. Zamyatin, Tatyana I. Gorbunova, A. A. Yushkov, Andrei N. Enyashin, A. S. Vorokh, A.M. Murzakaev, and E.S. Ulyanova
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Anatase ,Materials science ,Brookite ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nanocrystalline material ,0104 chemical sciences ,Amorphous solid ,Chemical engineering ,Mechanics of Materials ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,General Materials Science ,Crystallite ,0210 nano-technology ,High-resolution transmission electron microscopy ,Sol-gel - Abstract
The preferred local environment of CdS nanoparticles within the sol-gel synthesized TiO2/CdS composites with a multiphase titania matrix was unveiled in detail. Evolution of the environment was traced along the full path of the gel aging. HRTEM showed that the CdS particles are typically surrounded by amorphous titania within the composites based on complex amorphous-rich anatase/brookite matrix, while the brookite crystallites are more preferable in the vicinity of CdS within the composites with anatase/brookite matrix. Transformation path from amorphous into crystalline titania phases in the vicinity of CdS nanoparticles is seemingly regulated by the cohesion between titania and CdS, which degree has been estimated on the models of "core-shell" CdS@TiO2 composite nanoparticles as a function of titania polymorphism. MD simulations demonstrate that the thermodynamic stability and the interface interaction decrease in the series of amorphous titania, nanocrystalline brookite, nanocrystalline anatase. The structural analysis reveals that, in contrast to anatase, the enhanced CdS||TiO2 interface interaction in the case of brookite is due to a genuinely more distorted lattice of brookite, hence, due to its better match to a foreign irregular interface. It is suggested that the TiO2/CdS composites with the prevalent brookite surrounding of CdS nanoparticles can exhibit enhanced photocatalytic activity compared to the composites with a random anatase/brookite surrounding of CdS nanoparticles, since brookite has a moderate depth of electron traps. more...
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- 2020
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18. Effect of doping with 3d elements (Co, Ni, Cu) on the intrinsic defect structure and photocatalytic properties of nanostructured ZnO with tubular morphology of aggregates
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Inna V. Baklanova, Vladimir N. Krasil’nikov, M. Yu. Yanchenko, M. A. Melkozerova, L. Yu. Buldakova, Elizaveta V. Shalaeva, and Olga I. Gyrdasova
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Materials science ,Dopant ,Hydroquinone ,Absorption spectroscopy ,Band gap ,Doping ,Analytical chemistry ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Photocatalysis ,Electron paramagnetic resonance ,Solid solution - Abstract
The precursor-derived nanostructured solid solutions Zn0.95M0.05O (M = Co, Ni, Cu) with tubular aggregates have been investigated using optical absorption spectroscopy and electron paramagnetic resonance. The dependences of the concentration of intrinsic defects Vo+ and the effective band gap on the dopant type have been determined. It has been shown using the oxidation reaction of hydroquinone dissolved in water as an example that an increase in the photocatalytic activity in the series ZnO → Zn0.95Ni0.05O → Zn0.95Co0.05O Zn0.95Cu0.05O in the ultraviolet and visible spectral regions correlates with a decrease in the band gap and with an increase in the concentration of oxygen vacancies VO+. more...
- Published
- 2013
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19. Structural features and enhanced high-temperature oxygen ion transport in SrFe1−Ta O3−
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Mikhail V. Patrakeev, Vasily V. Kuchin, Victor L. Kozhevnikov, Elizaveta V. Shalaeva, Alexander P. Tyutyunnik, I. A. Leonidov, and Alexey A. Markov
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Materials science ,Inorganic chemistry ,Doping ,Oxide ,Analytical chemistry ,chemistry.chemical_element ,Conductivity ,Condensed Matter Physics ,Oxygen ,Grain size ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Phase (matter) ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,Stoichiometry - Abstract
Structural features, oxygen non-stoichiometry and transport properties are studied in the oxide series SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}}, where x=0.2, 0.3 and 0.4. X-ray diffraction and electron microscopy data evidence formation of the inhomogeneous materials at x=0.3 and 0.4, which include phase constituents with a cubic perovskite and a double perovskite structure types. The composition, the amount and the typical grain size of the phase inhomogeneities are shown to depend both on doping and oxygen content. The increased oxygen-ion conductivity is observed in oxygen depleted materials, which is explained by the increase in the amount of cubic perovskite-like phase and development of interfacial pathways favorable for enhanced oxygen ion transport. - Graphical abstract: The structural studies, oxygen content and conductivity measurements suggest that oxygen depletion from the double perovskite phase constituent of SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}} for x>0.2 is accompanied by formation of pathways for fast ion transport. Black-Small-Square Highlights: Black-Right-Pointing-Pointer The double perovskite type regions are shown to exist in SrFe{sub 1-x}Ta{sub x}O{sub 3-{delta}}. Black-Right-Pointing-Pointer The oxygen depletion is accompanied with phase separation. Black-Right-Pointing-Pointer The phase separation favors formation of pathways for enhanced oxygen ion transport. more...
- Published
- 2013
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20. Synthesis, microstructure, and native defects of photoactive Zn1 − x Cu x O solid solutions (0 ≤ x ≤ 0.1) with tubular aggregates
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E. V. Zabolotskaya, M. Yu. Yanchenko, Vladimir N. Krasil’nikov, M. A. Melkozerova, Olga I. Gyrdasova, L. Yu. Buldakova, Elizaveta V. Shalaeva, and V. G. Bamburov
- Subjects
Crystallography ,chemistry ,Thermal decomposition ,chemistry.chemical_element ,General Chemistry ,Zinc ,Microstructure ,Tubular aggregates ,Solid solution - Published
- 2012
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21. Nature of defects in nanocrystalline zinc oxide with particles of tubular morphology
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Elizaveta V. Shalaeva, M. A. Melkozerova, E. V. Zabolotskaya, Olga I. Gyrdasova, Rina F. Samigullina, and Vladimir N. Krasil’nikov
- Subjects
Morphology (linguistics) ,Inorganic chemistry ,g-factor ,chemistry.chemical_element ,General Chemistry ,Zinc ,Oxygen ,Nanocrystalline material ,law.invention ,chemistry ,Chemical engineering ,law ,Photocatalysis ,Electron paramagnetic resonance ,Line (formation) - Abstract
Nanostructured ZnO powders with particles of tubular form were synthesized by a precursor method. A narrow symmetrical line with a g factor of 2.002 was detected in the ESR spectra of the materials. On the basis of analysis of the dependence of the line intensities on the heat treatment conditions it was concluded that the signal belongs to singly charged oxygen vacancies V O + . more...
- Published
- 2012
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22. Planar defects in the icosahedral phase in quasicrystal-forming AlCuFe alloys
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S. Z. Nazarova, V. V. Khiller, Elizaveta V. Shalaeva, and A. F. Prekul
- Subjects
Diffraction ,Materials science ,Solid-state physics ,Condensed matter physics ,Icosahedral symmetry ,Phonon ,Quasiperiodic function ,Phase (matter) ,Quasicrystal ,Phason ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Abstract
Electron microscopy has revealed that, upon the formation of a stable icosahedral (i) AlCuFe phase, there arise a large number of planar defects. The revealed defects are nanometer-sized coherent intergrowths of the P1-pentagonal approximant. It has been found that the formation of these defects is the result of a nonequilibrium intermediate transformation. The intergrowths are located in the planes with the fivefold symmetry axis and give rise to an elastic-strain state of the i-phase. Analysis of the diffraction contrast has revealed the presence of phason and phonon atomic displacements due to the mismatch between the quasiperiodic (i-phase) and periodic (P1-phase) lattices. The formed structure exhibits a higher electrical resistance as compared to the i-phase and has been considered as a model state of the imperfect icosahedral phase with preferred phonon displacements. more...
- Published
- 2012
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23. Synthesis and structure of quasi-one-dimensional zinc oxide doped with manganese
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Elizaveta V. Shalaeva, M. V. Kuznetsov, Olga I. Gyrdasova, Vladimir N. Krasil’nikov, and Alexander P. Tyutyunnik
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Materials science ,Materials Science (miscellaneous) ,Doping ,Inorganic chemistry ,Analytical chemistry ,chemistry.chemical_element ,Zinc ,Manganese ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,X-ray photoelectron spectroscopy ,Transmission electron microscopy ,Surface layer ,Crystallite ,Physical and Theoretical Chemistry ,Ethylene glycol - Abstract
Nanotubes of manganese-doped zinc oxide Zn1 − xMnxO (0 ≤ x ≤ 0.2) were synthesized by heating the Zn1 − xMnx(HCOO)(OCH2CH2O)1/2 precursor in air at 500°C. The precursor with extended crystals was synthesized by a solvothermal method based on heat treatment of a mixture of Zn1 − xMnx(HCOO)2 · 2H2O with an ethylene glycol excess at 100–130°C. The tubular morphology of Zn1 − xMnxO particles was identified by transmission electron microscopy. Tubular quasi-one-dimensional particles were shown to have a nanodispersed polycrystalline structure, the size of separate crystallites being from 5 to 20 nm. X-ray photoelectron spectroscopy suggested that the manganese distribution on the outer surface layer of Zn1 − xMnxO nanotubes is nonuniform. more...
- Published
- 2012
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24. Calorimetric investigation of electronic and lattice excitations of the icosahedral quasicrystal in the range of moderate temperatures
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N. I. Shchegolikhina, A. F. Prekul, and Elizaveta V. Shalaeva
- Subjects
Materials science ,Fractal ,Condensed matter physics ,Solid-state physics ,Icosahedral symmetry ,Lattice (order) ,Quasicrystal ,Schottky diode ,Thermodynamics ,Atmospheric temperature range ,Condensed Matter Physics ,Spectral line ,Electronic, Optical and Magnetic Materials - Abstract
The precise measurements of the specific heat and the linear expansion coefficient of polygrain samples of the ordered icosahedral phase Al63Cu25Fe12 have been performed in the temperature range 1.8–400.0 K. The deviations from the Gruneisen law, according to which the temperature dependences of the lattice specific heat at constant volume and the linear expansion coefficient are identical to each other, have been analyzed. The proofs that the specific heat of the quasicrystals contains latent electronic and lattice contributions of the Schottky type have been obtained. The revealed contributions can be thermodynamic consequences of the fractal energy spectra. more...
- Published
- 2010
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25. Structural phase transformations in quasicrystal-forming Al-Cu-Fe alloys and defects of the icosahedral phase
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A. F. Prekul and Elizaveta V. Shalaeva
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Materials science ,Icosahedral symmetry ,Alloy ,Quasicrystal ,engineering.material ,Condensed Matter Physics ,Isothermal process ,Crystallography ,Planar ,Transmission electron microscopy ,Phase (matter) ,Materials Chemistry ,engineering ,Solid solution - Abstract
Transmission electron microscopy was used to investigate structural and phase transformations and defects of the icosahedral (ι) phase that is formed upon isothermal annealings (Tann = 550–700°C) of quenched quasicrystal-forming alloys Al61Cu26Fe13 and Al63Cu25Fe12 (β solid solution + ι phase). It has been established that in the Al63Cu25Fe12 alloy there occurs a reversible ι-R-approximant transformation, whereas in the Al61Cu26Fe13 alloy there is formed a single-phase ι structure with regions with a high density of randomly distributed planar defects (Tann = 550°C), which are partially annealed at 650°C. The observed defects are, mainly, ultrathin interlayers (“intergrowths” to 3–5 nm in thickness) on quasicrystal planes with A5ι axes with an imperfect decagonal structure. As the basic mechanism, the growth mechanism of the formation of defects during the β → i transformation is proposed. The role of the alloy composition and low-temperature β → 3C-phase transformation in the realization of this mechanism is discussed. more...
- Published
- 2010
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26. Photoelectron spectroscopy and diffraction of surface nanoscale NbO/Nb(110) structures
- Author
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Elizaveta V. Shalaeva, M. V. Kuznetsov, and A. S. Razinkin
- Subjects
Niobium ,chemistry.chemical_element ,Inorganic Chemistry ,Crystal ,Crystallography ,Molecular geometry ,chemistry ,X-ray photoelectron spectroscopy ,Chemical bond ,Monolayer ,Materials Chemistry ,Niobium oxide ,Physical and Theoretical Chemistry ,Natural bond orbital - Abstract
X-ray photoelectron spectroscopy and diffraction (XPS and XPD) are applied to analyze oxygen-induced surface structures on the Nb(110) face formed due to oxygen segregation from the crystal bulk on thermal annealing to 2000 K in vacuum and/or oxygen adsorption in situ at temperatures above 1100 K. The Nb3d, O1s electronic states and valence band spectra of the NbOx/Nb(110) surface are studied by XPS, and the results are compared with data for NbO, NbO2, and Nb2O5 oxides. It is shown that niobium atoms entering the composition of surface oxide structures on Nb(110), from the standpoint of the nearest environment and chemical bond, are similar to metal states in NbO. The NbOx layer thickness is estimated to be 0.5 nm. Two chemically inequivalent oxygen states are distinguished on Nb(110), which are, presumably, atomic chemisorbed oxygen on the parts of the clean surface of the Nb monolayer with hexagonal packing and oxygen in the composition of NbOx-like linear clusters on Nb(110). A model of the NbOx/Nb(110) surface takes into account a distortion of the structure of NbOx clusters: a periodic vertical shift of metal atoms in Nb-chains and changes in Nb-O bond angles. more...
- Published
- 2009
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27. Surface quasi-ordered nanostructures NbO x /Nb(110): investigation by surface analysis methods
- Author
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A. S. Razinkin, M. V. Kuznetsov, and Elizaveta V. Shalaeva
- Subjects
Nanostructure ,Materials science ,Niobium ,General Physics and Astronomy ,chemistry.chemical_element ,Metal ,Chemical state ,Crystallography ,chemistry ,Chemical bond ,X-ray photoelectron spectroscopy ,visual_art ,Monolayer ,visual_art.visual_art_medium ,Natural bond orbital - Abstract
The oxygen-induced surface structure on the Nb(110) face have been investigated by X-ray photoelectron spectroscopy and X-ray photoelectron diffraction. It is shown that the states (in terms of coordination and chemical bonding) of the niobium atoms belonging to surface oxide structures on Nb(110) are similar the metallic states in NbO. The thickness of the NbOx layer was estimated to be 0.5 nm. Two nonequivalent chemical states of oxygen atoms on Nb(110) have been selected. It is suggested that the first state is the chemisorbed state of atomic oxygen on hexagonally packed surface areas of a Nb monolayer surface and the second state is the state of oxygen atoms belonging to NbOx-like linear streaks formed on the Nb(110) face. more...
- Published
- 2008
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28. Investigation of the conditions for synthesis of Ce0.9Y0.1O2 dense coatings
- Author
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Elizaveta V. Shalaeva, Yu. A. Bakhteeva, I. A. Leonidov, and Victor L. Kozhevnikov
- Subjects
Materials science ,Annealing (metallurgy) ,Oxide ,Recrystallization (metallurgy) ,Condensed Matter Physics ,Microstructure ,chemistry.chemical_compound ,chemistry ,Transmission electron microscopy ,visual_art ,Screen printing ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,Ceramic ,Composite material ,Ethylene glycol - Abstract
The conditions for preparation of Ce0.9Y0.1O2 (CYO) oxide coatings on La0.8Sr0.2MnO3 (LSM) ceramic substrates by screen printing were investigated. The CYO compound was synthesized by the pyrolysis of polymer-salt composites with the aim of producing submicron powders with a uniform size distribution. Transmission electron microscopy of the microstructure of the CYO compound synthesized with ethylene glycol revealed that the synthesis product consists of ultrafine crystalline particles with an average size of 5–15 nm. The use of CYO nanopowders made it possible to prepare rather dense single-layer coatings on LSM substrates. It was demonstrated that annealing of the coatings at high temperatures leads to the recrystallization and coarsening of particles. more...
- Published
- 2008
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29. Photoelectron spectroscopy and diffraction of NbO x /Nb(110) surface
- Author
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M. V. Kuznetsov, A. S. Razinkin, and Elizaveta V. Shalaeva
- Subjects
Niobium ,chemistry.chemical_element ,Condensed Matter Physics ,Oxygen ,Crystal ,Metal ,Monatomic ion ,Crystallography ,Molecular geometry ,X-ray photoelectron spectroscopy ,Chemical bond ,chemistry ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium - Abstract
Methods of X-ray photoelectron spectroscopy and diffraction were used to investigate the oxygen-induced surface structures on the Nb(110) face which were formed as a result of oxygen segregation from the volume of the crystal upon thermal annealing at 2000 K in a vacuum and/or oxygen adsorption in situ at temperatures higher than 1100 K. The niobium atoms on the crystal surface form quasi-ordered structures in the form of monatomic Nb chains surrounded by oxygen atoms and from the viewpoint of the nearest surroundings and chemical bonding they are close to the states of the metal in NbOx. The thickness of such NbOx-like structure is estimated as 0.5 nm at the degree of coverage of the surface of 50%. Two chemically nonequivalent states of oxygen at Nb(110) have been distinguished, supposedly, (1) atomic chemisorbed oxygen on the surface of Nb metal and (2) oxygen in the composition of NbOx-like clusters on the Nb(110) plane. The NbOx/Nb(110) model of the surface allows for the distortion of the structure of NbOx clusters, i.e., periodic atomic displacements of metal atoms in Nb chains by height and changes in the Nb-O bond angles. more...
- Published
- 2008
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30. Ab initio calculations of the stability and structural defects of the B2 CuxFe1−x Al phases
- Author
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N. I. Medvedeva, Elizaveta V. Shalaeva, and I. R. Shein
- Subjects
Condensed Matter::Materials Science ,Materials science ,Condensed matter physics ,Magnetic moment ,Solid-state physics ,Ab initio quantum chemistry methods ,Physics::Atomic and Molecular Clusters ,Ab initio ,Shell (structure) ,Condensed Matter Physics ,Stability (probability) ,Electronic, Optical and Magnetic Materials - Abstract
The stability of the B2 CuxFe1−x Al phases and the energy of defect formation are studied using ab initio band calculations. For B2 CuxFe1−x Al alloys, vacancies in the 3d-metal sublattice and configurations with the minimum number of Fe-Cu bonds in the first coordination shell (including Fe antisite defects, which have a high local magnetic moment) are most stable. Complicated defect complexes with vacancies and displaced atoms, which are close to the atomic configurations of vacancy-ordered AlCu phases, can exist near the composition Cu0.875Fe0.125Al. more...
- Published
- 2007
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31. Investigation of quasicrystalline Al62.5Cu25Fe12.5 and crystalline β-Al50Cu33Fe17 alloys by X-ray photoelectron spectroscopy
- Author
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Elizaveta V. Shalaeva, A. F. Prekul, M. V. Kuznetsov, and N. I. Shchegolikhina
- Subjects
Materials science ,Icosahedral symmetry ,Alloy ,Fermi level ,Analytical chemistry ,General Physics and Astronomy ,Electron ,engineering.material ,Spectral line ,symbols.namesake ,Nuclear magnetic resonance ,X-ray photoelectron spectroscopy ,Phase (matter) ,engineering ,symbols ,Solid solution - Abstract
The electronic spectra of the valence band and core levels of the surface of polygrain alloys with the icosahedral structure and the β-(CsCl)-type solid solution of Al50Cu33Fe17 were investigated by X-ray photoelectron spectroscopy (XPS). The obtained XPS spectra of the Al62.5Cu25Fe12.5 alloy, in comparison with those of the crystalline Al50Cu33Fe17 alloy demonstrate narrowing and a decrease in asymmetry of the Fe2p core level and a decrease in the electron state density N(EF) near the Fermi level, features expected for the poorly conducting icosahedral phase. The XPS data are compared with the estimates of N(EF) based on the low-temperature specific heat measurements. more...
- Published
- 2007
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- View/download PDF
32. Effects of atomic relaxation and the electronic structure of niobium (100) and (110) surfaces
- Author
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K. I. Shein, M. V. Kuznetsov, I. R. Shein, Alexander L. Ivanovskii, Elizaveta V. Shalaeva, and N. I. Medvedeva
- Subjects
Surface (mathematics) ,Chemistry ,Fermi level ,Niobium ,chemistry.chemical_element ,Charge density ,Electronic structure ,Condensed Matter Physics ,Spatial distribution ,Molecular physics ,symbols.namesake ,Metallic materials ,Materials Chemistry ,symbols ,Relaxation (physics) ,Atomic physics - Abstract
A comparative analysis of the atomic relaxation and electronic structure of niobium (100) and (110) surfaces has been carried out using the VASP-PAW method. The relaxation-induced changes in interlayer spacings of surface layers demonstrate an oscillating behavior but they substantially differ for the two analyzed surfaces; namely for the (110) surface with the closest atomic packing two outermost surface layers are contracted by 4.3% and the relaxation becomes noticeable for three outer layers, while for the more “open” (100) surface these quantities equal 13.1 and six layers, respectively. An analysis of the layer-by-layer distribution of the densities of states, spatial distribution of the charge density, and densities of states at the Fermi level indicates that the most considerable changes near Fermi level take place for (100) surface. more...
- Published
- 2006
- Full Text
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33. Orientation relationships between the icosahedral phase and β solid solution in quasicrystal-forming quenched Al61Cu26Fe13 alloys
- Author
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A. F. Prekul and Elizaveta V. Shalaeva
- Subjects
Orientation (vector space) ,Crystallography ,Materials science ,Icosahedral symmetry ,Materials Chemistry ,Quasicrystal ,Beta (velocity) ,Type (model theory) ,Condensed Matter Physics ,Realization (systems) ,Solid solution ,Bar (unit) - Abstract
Electron microscopy has been used to study orientation relationships (ORs) and stable misorientations between corresponding directions of the icosahedral ι phase and the β phase (CsCl type structure) of the solid solution in quenched two-phase Al61Cu26Fe13 alloys with a dendritic structure. Calculated values of the azimuthal misorientations have been obtained for the directions of the reciprocal lattices of the ι and β phases in diffraction patterns A5l,[113]β; A2l, [111]A5β for the basic \(OR[110]_\beta \left\| {A5_l , [\bar 11\bar 1]_\beta } \right\|A2_l \) and close orientation conditions such as \([110]_\beta \left\| {A5_l , [\bar 110]_\beta } \right\|A2_l ; [11\bar 1]_\beta \left\| {A3_l , [\bar 110]_\beta } \right\|A2_l ; [111]_\beta \left\| {A2_l , [\bar 110]_\beta } \right\|A2_l \). Two possible mechanisms of stabilization of the azimuthal misorientations revealed are discussed; first, the realization of the \(OR[111]_\beta \left\| {A2_l , [\bar 110]_\beta } \right\|A2_l \) in quenched Al-Cu-Fe alloys and, second, the stability of the arising misorientations as a result of the formation of a layer with a modulated icosahedral structure at the boundaries between the β and gi phases. more...
- Published
- 2006
- Full Text
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34. XPS and XPD investigation of (112) CuInSe2 and Cu(InGa)Se2 surfaces
- Author
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M. V. Kuznetsov, Elizaveta V. Shalaeva, A.G. Panasko, and M. V. Yakushev
- Subjects
Diffraction ,biology ,Inga ,Annealing (metallurgy) ,Hexagonal crystal system ,Chemistry ,Metals and Alloys ,Stacking ,Analytical chemistry ,Surfaces and Interfaces ,engineering.material ,biology.organism_classification ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,Sphalerite ,X-ray photoelectron spectroscopy ,Materials Chemistry ,engineering - Abstract
The (1 1 2) surfaces of CuInSe 2 and Cu(InGa)Se 2 single crystals were studied using X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) techniques after ion-beam cleaning and annealing at 660 °C. Analysis of the experimental data suggested the presence of a structure crystallographically relative to sphalerite on the surface. The three possible choices of such a structure are discussed: (1) a sphalerite-based structure with the composition Cu(InGa) 3 Se 5 , (2) a mixture of In 2 Se 3 and Cu 2 Se and (3) Cu(InGa)Se 2 mixed with In 2 Se 3 . Theoretical simulations of the XPD experimental data supported the presence on the surface either of a Cu(InGa) 3 Se 5 structure with hexagonal stacking faults or a mixture of the phases Cu(InGa)Se 2 and γ-In 2 Se 3 . more...
- Published
- 2004
- Full Text
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35. X-Ray Photoelectron Diffraction. Possibilities of Surface Structural Analysis
- Author
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Elizaveta V. Shalaeva and M. V. Kuznetsov
- Subjects
Diffraction ,Solid-state physics ,Scattering ,Chemistry ,business.industry ,Plane wave ,Holography ,X-ray ,Molecular physics ,law.invention ,Inorganic Chemistry ,Optics ,Adsorption ,law ,Physics::Atomic and Molecular Clusters ,Materials Chemistry ,Physical and Theoretical Chemistry ,business ,Spectroscopy - Abstract
The current state of the X-ray photoelectron diffraction (XPD) method and its applications to solid state surface chemistry are overviewed in a systematic way. The fundamentals of the method are presented along with a number of approaches to its description: plane wave and spherical wave single scattering approximation, spherical wave multiple scattering approximation, and direct scattering and s-photoelectron scattering approximation. The role of the initial and final states of the photoelectron wave is demonstrated, and variants of XPD with scanning over angles and energies are described. The photoelectron holography formalism is given. Application of photoelectron diffraction to surface studies of single crystals, epitaxial layers, and metal–gas adsorption systems with the adsorbate localized on the surface and in subsurface layers is considered. The available experimental data are discussed. Photoelectron diffraction calculations in single and multiple scattering approximations are assessed. The bibliography on XPD application to studies of various surface and adsorption systems is given. more...
- Published
- 2003
- Full Text
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36. On mutual transformations of icosahedral phase and β-solid solution with participation of ordered ω-like displacements in quenched alloys of Al61Cu26Fe13
- Author
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Elizaveta V. Shalaeva
- Subjects
Solid structure ,Condensed matter physics ,Chemistry ,Icosahedral symmetry ,Mechanical Engineering ,Beta phase ,Metals and Alloys ,Iron alloys ,Crystallography ,Electron diffraction ,Mechanics of Materials ,Transmission electron microscopy ,Lattice (order) ,Materials Chemistry ,Solid solution - Abstract
In the rapidly-quenched alloys of Al61Cu26Fe13 characteristic orientation relationships were found between the lattice of the icosahedral phase (ι-phase) and that of the β(CsCl)-solid solution (where β-solid solution contains fine regions of ω-like displacements): [111]β || A2, [110]β || A5. It was established that at the ι-phase (dendrite)/β-solid solution (interdendritic layers) boundary areas there was a state formed with a modulated structure of the ι-phase. It is assumed that the fine regions of ordered ω-like displacements are involved in the continuous transformations (direct and reverse) ι-phase→modulated ι-structure→heterogeneous β-solid solution, going on in the boundary areas due to the strained state of quenched alloys. more...
- Published
- 2002
- Full Text
- View/download PDF
37. Structural, Optical, and Photocatalytic Properties of Quasi-One-Dimensional Nanocrystalline ZnO, ZnOC:nC Composites, and C-doped ZnO
- Author
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Vladimir N. Krasil’nikov, Elizaveta V. Shalaeva, Olga I. Gyrdasova, Inna V. Baklanova, M. A. Melkozerova, and L. Yu. Buldakova
- Subjects
symbols.namesake ,Amorphous carbon ,Transmission electron microscopy ,Specific surface area ,Photocatalysis ,symbols ,Thermal treatment ,Crystallite ,Composite material ,Raman spectroscopy ,Nanocrystalline material - Abstract
Various thermolysis rotes of zinc glicolate complexes are considered for the synthesis of quasi-one-dimensional nanostructured aggregates ZnO and Zn–O–C used as photocatalysts. Structural features of quasi-one-dimensional aggregates Zn–O–C and ZnO are investigated in detail. Transmission electron microscopy, Raman spectroscopy, and electron paramagnetic resonance spectroscopy methods demonstrate that the aggregates Zn–O–C have either composite structure (ZnO crystallites in amorphous carbon matrix) or a C-doped ZnO single-phase structure depending on heat treatment conditions, and that all the aggregates exhibit as a rule a tubular morphology, a nanocrystalline structure with a high specific surface area, and a high concentration of singly charged oxygen vacancies. The mechanism of the nanocrystalline structure formation is discussed and the effect of thermolysis condition on the formation of the textured structure of aggregates is investigated. The results of examination of the photocatalytic and optical absorption properties of the synthesized aggregates are presented. The photocatalytic activity for the hydroquinone oxidation reaction under ultraviolet and visible light increases in the series: the reference ZnO powder, quasi-one-dimensional ZnO, quasi-one-dimensional aggregates C-doped ZnO, and this tendency correlates with the reduction of the optical gap width. As a result of our studies, we have arrived at an important conclusion that thermal treatment of ZnO:nC composites allows a C-doped ZnO with high catalytic activity. This increasing photoactivity of C-doped ZnO aggregates is attributed to the optimal specific surface area and electron-energy spectrum restructuring to be produced owing to the presence of singly charged oxygen vacancies and carbon dissolved in the ZnO lattice. more...
- Published
- 2014
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38. Synthesis, microstructure, and photocatalytic characteristics of quasi-one-dimensional zinc oxide doped with d elements
- Author
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Elizaveta V. Shalaeva, Olga I. Gyrdasova, M. Yu. Yanchenko, Vladimir N. Krasil’nikov, L. Yu. Buldakova, and V. G. Bamburov
- Subjects
chemistry ,Inorganic chemistry ,Doping ,Photocatalysis ,chemistry.chemical_element ,Quasi one dimensional ,General Chemistry ,Zinc ,Microstructure - Published
- 2010
- Full Text
- View/download PDF
39. Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13
- Author
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A. F. Prekul and Elizaveta V. Shalaeva
- Subjects
Chemistry ,Icosahedral symmetry ,Alloy ,Quasicrystal ,Dielectric ,State (functional analysis) ,engineering.material ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Crystallography ,Phase (matter) ,engineering ,Electron microscopic ,Solid solution - Abstract
Electron microscopic investigations of the structural state have been carried out for the β(CsCl-type)-phase in the quenched quasicrystal-forming two-phase (ι + β) alloy Al 61 Cu 26 Fe 13 . We conclude that in the vicinity of compositions at which the icosahedral phase (i) is formed, at deviations from the composition Al 3 (Cu,Fe) 2 towards Al(Cu,Fe), the β(CsCl-type)-solid solution has a heterogeneous structure (a state similar to the diffuse incommensurable ω-phase in b.c.c.-solid solutions). This structure includes the β-matrix with fine regions of correlated ω-like displacements which in a certain way are interrelated with the τ 3 -short-range order of substitution. It is concluded that the β(CsCl-type)-phase of Al 61-x Cu 26+y Fe 13-z reveals structural signs typical for electron-stabilized solid solutions, and because of this, the β-phase demonstrates a dielectric behavior of its electronic properties. An assumption has been made that the regions with ω-displacements are involved in the structural transformation β-phase → ι-phase. more...
- Published
- 2000
- Full Text
- View/download PDF
40. Metastable phase diagram of Ti–Si–N(O) films ( C Si <30 at.%)
- Author
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O.F Denisov, S. V. Borisov, Elizaveta V. Shalaeva, and M. V. Kuznetsov
- Subjects
Supersaturation ,Silicon ,Metals and Alloys ,Nucleation ,Analytical chemistry ,Mineralogy ,chemistry.chemical_element ,Context (language use) ,Surfaces and Interfaces ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Crystal ,Condensed Matter::Materials Science ,chemistry ,Metastability ,Materials Chemistry ,Ternary operation - Abstract
Metastable ternary concentration diagram of phase formation in arc-deposited films Ti–Si–N(O) (CSi 10–15 at.% a transition takes place from metastable supersaturated cubic solution TiSixNyOz to amorphous state TiSixNyOz. Intermediate bi-phase area (TiSixNyOz + Ti5Si3 (O,N) with heterogeneous structure, preceding forming an amorphous state, was found. In the context of the heterogeneous nucleation, kinetics of the deposition of the phases TiSixNyOz, Ti5Si3(O,N) was analyzed. It was shown that heterogeneous microstructure of these films and concentration range (on silicon) of the forming bi-phase area is defined by energy parameters of growth kinetics of critical Ti5Si3 (O,N) crystal nucleus. Applicable to the system Ti–Si–N(O) (CSi more...
- Published
- 1999
- Full Text
- View/download PDF
41. Adsorption of carbon monoxide on Ti(0001)
- Author
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Elizaveta V. Shalaeva, M. V. Kuznetsov, N.I Medvedeva, and D. P. Frickel
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Radiation ,Chemistry ,Inorganic chemistry ,Kinetics ,chemistry.chemical_element ,Sorption ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Adsorption ,X-ray photoelectron spectroscopy ,Chemisorption ,Physical chemistry ,Physical and Theoretical Chemistry ,Carbon ,Spectroscopy ,Carbon monoxide ,Titanium - Abstract
This paper covers the kinetics and mechanism of dissociative chemisorption of carbon monoxide on the face Ti(0001) at a room temperature of T =300 K within the interval of adsorption exposure of 0–300 Langmuir. X-ray photoelectron spectroscopy and X-ray photoelectron diffraction were used to establish characteristics of initial elementary stages of chemisorption, to determine localization centers of adsorbed atoms and to distinguish between the different types of kinetics of filling in the non-equivalent sorption centers with carbon or oxygen atoms. A series of possible variants of the CO chemisorption on the Ti(0001) surface was calculated by the first-principal linear method of muffin-tin orbitals in the full-potential version (LMTO-FP). more...
- Published
- 1998
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42. XPS AND XPD ANALYSIS OF NITROGEN ADSORPTION ON THE <font>Ti</font>(0001) SURFACE
- Author
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M. V. Kuznetsov, Elizaveta V. Shalaeva, and D. P. Frickel
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Diffraction ,Kinetics ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Nitrogen adsorption ,Condensed Matter Physics ,Nitrogen ,Surfaces, Coatings and Films ,Adsorption ,chemistry ,X-ray photoelectron spectroscopy ,Monolayer ,Materials Chemistry ,Titanium - Abstract
X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) were used to examine the kinetics of nitrogen adsorption on the Ti(0001) surface at temperatures from 220 to 570 K and adsorption exposures from 0 to 1000 L. At the adsorption temperature T=300 K two chemically nonequivalent states of nitrogen were found: NI (1×1 lattice) localized in octapores between the first and second titanium monolayers and NII (presumably [Formula: see text] structure) on the titanium surface. The third nitrogen state, N0 , which is also localized on the surface but has unoccupied octapores in the nearest neighborhood, is observed with a decrease in the adsorption temperature to 220 K. A model of nitrogen interaction with the Ti(0001) surface in vacuum was proposed proceeding from the temperature dependence of the kinetic adsorption curves. more...
- Published
- 1997
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43. Metastable TiSixNyOz films of B1-type structure prepared by the arc process
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Elizaveta V. Shalaeva, B. V. Mitrofanov, M. V. Kuznetsov, Alexander L. Ivanovsky, and S. V. Borisov
- Subjects
Silicon ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Substrate (electronics) ,Electron microprobe ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,chemistry ,X-ray photoelectron spectroscopy ,Transmission electron microscopy ,Condensed Matter::Superconductivity ,Metastability ,Materials Chemistry ,Deposition (phase transition) ,Condensed Matter::Strongly Correlated Electrons ,Tin - Abstract
Metastable TiSi x N y O z films with the cubic B1-type structure were synthesized by arc deposition. X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and electron microprobe analysis (EMA) methods were employed to study the composition and structure of the films as a function of the arc process parameters: working gas pressure, substrate temperature and potential. It was established that silicon atoms are introduced into the B1-type structure of TiN y O z films and are located in the non-metallic sublattice. The influence of the non-metallic sublattice non-stoichiometry and oxygen impurity content on the silicon concentration in the films was discussed on the basis of the experimental data obtained and the quantum chemical calculations performed. more...
- Published
- 1996
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44. Structure and Stability of Nonstoichiometric Cubic Phase δ-NbN1.2(O, C)
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Elizaveta V. Shalaeva, B. V. Mitrofanov, and G. P. Shveikin
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Diffraction ,Reciprocal lattice ,Crystallography ,Condensed matter physics ,Chemistry ,Scattering ,Impurity ,Lattice (order) ,Crystal structure ,Thin film ,Nitride ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Abstract
The nonstoichiometric δ-niobium nitride with surplus content of nitrogen atoms and the NaCl-type structure (a = 0.439 nm), i.e. δ-NbN1.2(O, C), is stabilized in epitaxial deposited films. The diffraction patterns of these films display intensive diffuse scattering with regular intensity vanishings in the form of plane regions in the vicinity of structural and superstructural reciprocal space points of the δ-phase and in the form of spherical surfaces in the neighbourhood of structural points. The analysis performed shows that this scattering can be associated with the presence of mixed-nature short-range order regions in the nonstoichiometric δ-NbN1.2(O, C) phase which are characterized by longitudinal uncorrelated atomic displacement waves, as well as by concentration-type waves. The ordered oxycarbonitride phase (X-phase) described in the first approximation by the cubic lattice with parameter a = 0.392 nm is found to precipitate when annealing the films at T = 873 K. It has been established that the diffuse scattering occurring in δ-NbN1.2(O, C) and the structure of shortrange order regions exhibit certain correlation with the structure of the precipitated ordered phase — G100x ≈ 1.1G100δ = K1; G010x ≈ 1.1G010δ = K2 (where K1 and K2 are wave vectors of longitudinal atomic displacement waves characterizing short-range order). [Russian Text Ignored] more...
- Published
- 1996
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45. Phase separation-promoted ion conduction in SrFe0.67Ta0.33O3 (-) (delta) ceramics
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Mikhail V. Patrakeev, João C. Waerenborgh, Elizaveta V. Shalaeva, Ekaterina V. Tsipis, I. A. Leonidov, Vladislav V. Kharton, V.L. Kozhevnikov, Alexander P. Tyutyunnik, and Alexey A. Markov
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Materials science ,PEROVSKITE ,MOSSBAUER-SPECTROSCOPY ,FERRITES ,Inorganic chemistry ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,MIXED CONDUCTIVITY ,OXIDATION ,01 natural sciences ,Oxygen ,Ion ,Electrical resistivity and conductivity ,Mössbauer spectroscopy ,Brownmillerite ,General Materials Science ,Wüstite ,OXIDES ,TEMPERATURE ,Perovskite (structure) ,General Chemistry ,Partial pressure ,OXYGEN NONSTOICHIOMETRY ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,TRANSPORT ,0104 chemical sciences ,chemistry ,engineering ,0210 nano-technology ,VALENCES - Abstract
The electrical conductivity of SSrFe0.67Ta0.33O3 (-) (delta) measured in the oxygen partial pressure range from 10-2 to 0.5 atm at 700-950 degrees C, exhibits an anomalous and reversible increase in moderately reducing atmospheres, substantially contributed by oxygen ion transport. The coulometric titration studies in combination with the electron and X-ray diffraction analyses show that this trend correlates with the separation of oxygen-deficient disordered cubic perovskite and Ta-rich double perovskite domains of nanometer-scale size. Mossbauer spectroscopy demonstrated that the predominant state of iron cations in the vicinity of this transition is trivalent Further reduction leads to the formation of Fe2+ states responsible for increasing n-type electronic conductivity, whilst no traces of wustite or oxygen vacancy-ordered brownmillerite phases were detected. The ion conduction in partially reduced SrFe0.67Ta0.33O3 (-) (delta) is significantly higher compared to SrFe0.7Ta0.3O3 (-) (delta) and SrFe0.6Ta0.4O3 (-) (delta) under similar conditions, which may indicate an important role of the interfacial boundary enlarged due to the perovskite phase separation. 0 2013 Elsevier B.V. All rights reserved. more...
- Published
- 2013
46. Structure of epitaxial δ-NbN films deposited by cathode reactive sputtering
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M. V. Kuznetsov, Elizaveta V. Shalaeva, B. V. Mitrofanov, and R.S. Baryshev
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Coalescence (physics) ,Materials science ,Metals and Alloys ,Recrystallization (metallurgy) ,Cleavage (crystal) ,Surfaces and Interfaces ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,Electron diffraction ,Sputtering ,Transmission electron microscopy ,Materials Chemistry ,Thin film ,Crystal twinning - Abstract
The low-temperature (298–673 K) growth and structure of epitaxial δ-NbN thin films (100–800 A) deposited by reactive sputtering on the (100) NaCl cleavage surface have been studied by transmission electron microscopy. The films have a parallel epitaxial orientation (100)NaCl ∥ (100)NbN and contain microtwin interlayers in the (111) planes. The micro twin content dependence on the background pressure as well as on deposition rate has been found. It has been concluded that microtwins form at the initial growth stage as a result of coalescence of islands of different orientations, (100) and (111), like condensed fcc metal films. The high density of block boundaries and the distortion of coherent growth with small film thicknesses ( h ≈ 100 A ) are attributed to the high activation energy of coalescence and recrystallization processes characteristic of refractory compounds. more...
- Published
- 1995
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47. Optical and photocatalytic properties of quasi-one-dimensional ZnO activated by carbon
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Larisa Yu. Buldakova, Elizaveta V. Shalaeva, Mikhail Yu. Yanchenko, Olga I. Gyrdasova, Vladimir N. Krasil’nikov, M. A. Melkozerova, and Inna V. Baklanova
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Chemical engineering ,chemistry ,Photocatalysis ,chemistry.chemical_element ,Quasi one dimensional ,General Chemistry ,Carbon - Published
- 2014
- Full Text
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48. ChemInform Abstract: Cubic Solid-Solution TixSiyNz(O) Films: Synthesis, Structure and Electronic Properties
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S. V. Borisov, M. V. Kuznetsov, Elizaveta V. Shalaeva, B. V. Mitrofanov, G. P. Shveikin, and Alexander L. Ivanovsky
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Silicon ,Structure (category theory) ,chemistry.chemical_element ,General Medicine ,Condensed Matter::Materials Science ,chemistry ,Phase (matter) ,Metastability ,Physics::Atomic and Molecular Clusters ,Physical chemistry ,Condensed Matter::Strongly Correlated Electrons ,Physics::Atomic Physics ,Solid solution ,Titanium ,Electronic properties - Abstract
Monophase films of the metastable cubic phase Ti x Si y N z (O) with the B1 structure have been synthesized; introduction of silicon atoms into the non-metallic sublattice of titanium oxynitride has been proved experimentally and theoretically. more...
- Published
- 2010
- Full Text
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49. SYNTHESIS AND STRUCTURE OF NONSTOICHIOMETRIC δ-NbN1+y FILMS
- Author
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Elizaveta V. Shalaeva, R.S. Baryshev, M. V. Kuznetsov, and B. V. Mitrofanov
- Subjects
Chemistry ,Condensed Matter::Superconductivity ,[PHYS.HIST]Physics [physics]/Physics archives ,0103 physical sciences ,Structure (category theory) ,Analytical chemistry ,General Physics and Astronomy ,Physical chemistry ,01 natural sciences ,010305 fluids & plasmas - Abstract
The structural state of oriented nonstoichiometric δ-NbN1.2 films (NaCl-type structure) prepared by reactive ion plasma sputtering has been studied by transmission electron microscopy and photoelectron spectroscopy. An intensive diffuse scattering has been found on the microdiffraction patterns. The diffuse scattering distribution in the reciprocal space, the regularities of intensity vanishing, as well as the dependence of diffuse scattering on the N/Nb ratio, carbon and oxygen impurity atoms have been determined. It has been concluded that the diffuse scattering observed in δ-NbN films with a nitrogen content surplus (N/Nb=1.2) is caused by the atomic displacement wave spectrum in the range of [MATH] ([MATH] is a δ-NbN reciprocal lattice vector, [MATH] corresponding to 0.9 [MATH], 0.9 [MATH]). The atom displacement waves are possibly related to δ-NbN - Nb4N5 phase transition. more...
- Published
- 1991
- Full Text
- View/download PDF
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