Poverhnostʹ. Rentgenovskie, sinhrotronnye i nejtronnye issledovaniâ
The Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques (Poverkhnost'. Rentgenovskie, Sinkhrotronnye i Neitronnye Issledovaniya) publishes original experimental and theoretical articles and reviews on the most topical problems of surface phenomena, surface structure, physical and chemical properties, treatment and investigations of surfaces, as well as thin films, interfaces etc. Special attention is given to the use of X-ray, synchrotron and neutron methods of analysis.
The Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques is abstracted and/or indexed in:
Academic OneFile, Chemical Abstracts Service (CAS), EI-Compendex, Expanded Academic, Google Scholar, INSPEC, OCLC, SCImago, SCOPUS, Summon by ProQuest.
Current Issue



No 6 (2023)
Articles
Spin-Orbit Interactions in Osmium Complexes
Abstract
Osmium compounds with the Os5



Resonance Effects in Photoemission Spectroscopy of Rare-Earths in Intermetallic Compound LaTbMnSi
Abstract
The electronic structure of the rare-earth intermetallic compound La0.73Tb0.27Mn2Si2 has been studied by resonant photoemission spectroscopy using synchrotron radiation, and its formation patterns have been established upon partial replacement of lanthanum atoms by terbium. The dependence of the valence band spectra shape on the photon energy near the absorption edges of the internal levels of manganese, lanthanum, and terbium is analysed. The processes of direct and two-stage production of photoelectrons, elastic and inelastic decay channels of these states with the emission of high-energy electrons due to intra-atomic Coulomb interaction have been studied. The dominant mechanisms of the decay of the excited states of the components under study were determined from the shapes of the spectra. For rare-earth metals elastic decay channel of the excited state is the most probable, while for manganese, it is inelastic, with the formation of a second hole in the valence band with subsequent enhancement of photoemission. Exciting photoemission near



Application of Some Techniques Using Synchrotron Radiation to the Study of a Promising Composite Thermoelectric Material SrTiO–TiO
Abstract
The results of a study of biphase ceramics SrTiO3–TiO2, previously proposed as a promising



Polymethyl Methacrylate with a Molecular Weight of 10 g/mol for X-Ray Lithography
Abstract
The results of a study of syndiotactic polymethyl methacrylate with a molecular weight of 107 g/mol, synthesized via ionic polymerization with radiation initiation, are presented. Changes in the chemical structure of the polymer material have been analyzed by IR spectroscopy, differential thermal analysis, and gel permeation chromatography. During thermal decomposition of the initial polymer, the mass loss process can be divided into three stages: low-temperature, medium-temperature, and high-temperature. The pronounced thermal effect of polymer melting disappears even after exposure to minimal doses of ionizing radiation. A relatively rapid decrease in the molecular weight under the influence of X-ray radiation in the dose range up to 100 J/cm3 and a scatter in molecular sizes have been found. Polydispersity at low doses is approximately 3.5 times higher than that at doses of the order of 10 kJ/cm3. A latent image development rate of approximately five times higher than that of a polymer with a molecular weight of 106 g/mol under standard conditions was achieved. The contrast value was 3.4. Using X-ray synchrotron radiation at the VEPP-3 source, microstructuring was carried out by X-ray lithography. Microstructures up to 5 µm high and about 2 µm in diameter were obtained.



Modification of the Electronic Structure of Few-Layer Graphene Grown on β-SiC(001) by Neutral Red Dye
Abstract
Graphene layers on semiconducting substrates, modified using covalent and non-covalent chemical functionalization, can be utilized for fabrication of hybrid structures combining physical properties of graphene and organic molecules. In this paper the results of investigations of the atomic and electronic structure of ultrathin graphene layers on β-SiC/Si(001) wafers modified using phenazine dye Neutral Red are presented. Continuous graphene films consisting on several atomic layers were synthesized on β-SiC/Si(001) wafers using high-temperature annealing in ultrahigh vacuum. The synthesized graphene layers were chemically modified in a solution of diazonium salt of the Neutral Red dye under white light illumination. The results of the scanning tunneling microscopy and spectroscopy experiments demonstrate the formation of a composite phenazine/graphene structure with a large energy gap in all surface regions. The molecules can be oriented preferentially parallel and perpendicular to the graphene layers and form locally ordered structures with rectangular and oblique unit cells. The electronic energy spectrum and band energy gap in different surface areas depend on the local atomic structure and the molecule’s orientation relative to the surface. According to the density functional theory calculations, local modifications of the electronic structure and band energy gap can be related to deformations (compression or extension) of the phenazine dye molecules because of their interaction with the topmost graphene layer.



Molybdenum Texture Effect on High Temperature Oxidation Resistance of Cr/Mo-Coated Zr–1Nb Alloy
Abstract
The effect of the crystal structure of the Mo sublayer on the resistance of the Zr–1Nb zirconium alloy with a Cr/Mo coating to high-temperature oxidation in air were studied. Three types of coating were deposited by magnetron sputtering: a single-layer Cr coating with a thickness of 8 μm, bilayer coatings with a Mo sublayer (3 μm) of various textures and an outer protective Cr layer (8 μm). Different textures of molybdenum layers were formed by changing the configuration of the magnetron sputtering system. Coated samples were oxidized in an atmospheric furnace at 1100°C for 15, 30, 45 and 60 min. The results of X-ray diffraction and scanning electron microscopy showed that applying Mo sublayer limited the Cr–Zr interdiffusion. Diffusion of Mo leads to the formation of interdiffusion layers Cr–Mo and Mo–Zr. Faster diffusion is observed at the Cr–Mo interface. The thickness of the residual Cr layer in bilayer coatings is greater than in a single-layer one under similar oxidation conditions.



Effect of Microarc Oxidation Duration on the Characteristics of Thermal Control Coatings on Aluminum Alloy
Abstract
The influence of microarc oxidation process duration on the thickness, roughness and optical characteristics (solar absorbance αs and emissivity ε) of thermal control white and black cosmic coatings formed on an aluminum alloy AMg6 is studied experimentally. It is found that αs decreases with an increase in the thickness of coatings with increasing microarc oxidation treatment duration. For white coatings, a decrease in their roughness is accompanied by an increase in ε, and vice versa. For black coatings, the main role is played by the degree of blackness of the coating, which is determined by the content of vanadium oxide in it. A comparative analysis of the optical characteristics of thermally controlled coatings obtained using microarc oxidation process on various aluminum alloys showed that it is better to form white coatings of the “solar reflector” class on an aluminum alloy AMg3, and black coatings of the “true absorber” class – on an aluminum alloy AMg6 with MAO treatment duration of 25 min. The obtained experimental data can serve as a framework for the development of basic technology for the formation of thermal control cosmic coatings on products made of aluminum alloys.



Synthesis and Investigations of Morphology and Structure of FeO Nanocoatings on Porous AlO, Obtained by Oxidation of Magnetron Deposited Fe Films
Abstract
The results of studies of the morphology, crystal, local atomic and chemical structure of iron(III) oxide coatings on the surface of porous alumina with different morphology by scanning electron and atomic force microscopy, X-ray phase analysis, X-ray photoelectron spectroscopy, as well as fine structure spectroscopy of the near edge region are presented. X-ray absorption. Films of porous alumina were synthesized by the method of two-stage anodic oxidation of aluminum in aqueous 0.3 M solutions of sulfuric and oxalic acids. To change the pore diameter, some of the films were etched in a phosphoric acid solution. Samples of iron oxide nanocoatings were obtained by air oxidation of iron films deposited on porous alumina substrate matrices by magnetron sputtering at a temperature of 300°C for 3 hours. It is shown that oxidation leads to a twofold increase in the coating thickness of the control sample and is associated with an increase in the density of iron oxide compared to pure iron. With a change in the nanoporous structure on the surface of the substrates, the morphological features of the coatings change, which consists in the “overgrowth” of pores with iron oxide. That the control of the processes leading to such “overgrowth” will make it possible to carry out a directed change in the structure-sensitive properties of composite structures based on iron oxide.



Study of the Physical and Mechanical Properties of Coatings Obtained by Vacuum-Arc Spraying of Ti–B–Si–Ni Cathodes Manufactured Using Self-Propagent High-Temperature Synthesis and Pressing
Abstract
The article presents the results of a study of vacuum-arc coatings obtained by sputtering Ti–B–Si–Ni cathodes, manufactured by the method of self-propagating high-temperature synthesis with simultaneous pressing. The techniques for manufacturing cathodes of the indicated composition were characterized; the modernized NNV 6.6-I1 device, the conditions and modes of coating deposition in an argon atmosphere and in a nitrogen + argon gas mixture in a ratio of 90/10 were described. To study the physical and mechanical properties of the resulting coatings, the hardness was measured at different loads on the indenter; the strength of adhesion to the base was assessed by the Rockwell method; the elemental composition of the cathodes and the (Ti–B–Si–Ni)N coating was determined by Auger spectroscopy and the phase composition of the (Ti–B–Si–Ni)N coating was determined by X-ray phase analysis; a study of the properties of the coating (Ti–B–Si–Ni) was carried out by the scratching method (scratch testing). As a result of a comprehensive analysis of the results obtained, it was concluded that the high hardness of the (Ti–B–Si–Ni)N coating (more than 40 GPa) is due to its composition, which includes both nitrides and highly hard titanium borides. The heterophasic nature of the structure of this coating can serve as a contribution to the stressed state of the material. The coating has a gradient-layered structure. The material contains a Ti–B–Si–Ni layer bonding with the substrate and the main functional layer (Ti–B–Si–Ni) N. The coating has both high hardness and sufficient adhesion to the substrate (adhesion) determined by the scratch testing. The combination of these properties makes the material promising for its practical application in the production of tools.



Substitution in the Structure of Hydroxyapatite Doped by Iron Cations at Mechanochemical Synthesis
Abstract
Hydroxyapatite, a mineral of the apatite group, has an important and useful property – the propensity for various kinds of substitutions, which allows to modify its properties and expand the possibilities of using the synthetic material. The properties of the synthesised substance depend on the way it is produced, as the synthesis conditions influence the structural and morphological characteristics of the particles being formed. This paper shows that at mechanochemical synthesis with the introduction of iron cations as a dopant the structure of hydroxyapatite, in which the dopant occupies the position of the calcium cation, is formed. This type of substitution is accompanied by a decrease in the lattice parameters of the hydroxyapatite. It is shown that iron cations have predominantly a 3+ charge, which is independent of the charge of the initial reagent containing the iron cation. It was also found that in the process of mechanochemical synthesis under certain conditions, simultaneous partial replasement of calcium cations with iron cations and phosphate group with carbonate group can be realized. The powders obtained by mechanochemical synthesis were characterized by powder diffraction, infrared spectroscopy, near-edge X-ray absorption fine structure spectroscopy and Mössbauer spectroscopy.



X-Ray Diffraction Study of Mn–Ce Catalysts for CO Oxidation
Abstract
A series of MnO



Spontaneous Formation of Potassium Hydrofluoride during Aging of a Partially Dehydrofluorinated PVDF Film
Abstract
IR spectroscopy, X-ray phase analysis and scanning electron microscopy were used to study the spontaneous formation and increase in the amount of potassium hydrofluoride in the inner region of a sample of a partially chemically dehydrofluorinated PVDF film during its long-term aging. The most probable mechanism for the synthesis of potassium hydrofluoride is the oxidative degradation of the sample with the formation of fluorocarbonyl groups and their subsequent hydrolysis under the action of atmospheric water. This results in the formation of hydrogen fluoride, which combines with potassium fluoride, a by-product of primary dehydrofluorination. The increase in the content of potassium hydrofluoride continues as the sample ages until potassium fluoride remains in it. The appearance and subsequent development of spectral features characteristic of libration out-of-plane vibrations of water tetramers indicates the formation of a system of nanometer-sized pores in the sample after 100 000 min of its aging.



Quantum Tunneling Effect on the Transverse Motion Energy Spectrum for the Channeling Positrons in the Silicon Crystal
Abstract
The charged particles motion in the crystal could be either regular or chaotic. In the quantum picture the chaos manifests itself in the statistical properties of the energy levels set. The systems with regular motion domains in the phase space separated by the chaotic one are of a particular interest. The possibility to tunnel between dynamically isolated domains of the phase space influences essentially on the energy levels statistics. This effect account leads to Podolskiy–Narimanov distribution function. The tunneling matrix elements for the transversal motion of 20 and 40 GeV positrons axially channeled in [100] direction of Si crystal are estimated in the present paper. The parameter of the Podolskiy–Narimanov distribution is derived from this estimation. It is demonstrated that this distribution successfully describes the level spacing statistics for the energy levels set of the positron transversal motion.



Monte Carlo Computer Simulation Method for Solving the Problem of Particle Passage through Matter
Abstract
The Monte Carlo method is compared with the deterministic methods based on the solution of the transport equation and the molecular dynamics methods. The capabilities of commonly used general-purpose programs (SRIM, PENELOPE, MCNP, FLUKA, and GEANT4) for Monte Carlo simulation of the processes of particle passage through matter are analyzed. Possible ways for further development of the Monte Carlo method are discussed.



A Comprehensive Study of the Local Atomic Structure of Promising Ti-Containing Compounds
Abstract
A comprehensive study of the local atomic structure of titanium compounds obtained by mechanical activation (Ti–Al–C, Ti2AlC) and reference samples (Ti, TiH2) using EXAFS and EXELFS spectroscopy has been carried out. An analysis of the local atomic structure of titanium hydride shows that the presence of hydrogen expands the crystal lattice and leads to a change in the parameters of the local atomic structure. This change is observed both in the EXAFS and EXELFS spectra. It is shown that after mechanical activation, the coordination numbers decrease, which may indicate the formation of a multiphase system. Further annealing leads to the formation of the Ti2AlC compound, which is confirmed by the results of model calculations.


