bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Resonant Scattering of Channeling Particles with the Generation of Electron and Phonon Excitations
Authors: Mazur E. A.
Published: April 2024

The effects of resonant scattering of fast relativistic leptons directed at small angles relative to a selected crystallographic plane are considered. Simultaneously, the processes of radiation and generation of excitations in crystals by a collimated beam of channeled leptons entering a single crystal at small angles (both greater and less than the Lindhard angle \({{\theta }_{{\text{L}}}}\)) are considered from a unified point of view. The processes of Raman scattering of a monochromatic electromagnetic wave by channeled relativistic leptons (electrons, positrons), which experience the effect of resonant scattering at a small angle of entry relative to a selected crystallographic plane are theoretically studied, as well as the processes of Raman scattering by a relaxing deeply nonequilibrium electron-phonon system of the semiconductor, excited by a relativistic beam of charged leptons of subnanosecond duration directed at a small angle \(\left( {\theta {{\theta }_{{\text{L}}}}} \right)\) to the crystallographic plane.
Study of Modification of the Inner Surface of the Hollow Poly-Sulphone Fiber Channels When Irradiated by a Beam of Electrons of Energy 10 keV
Authors: Myshelovka L. V. , Vokhmyanina K. A. , Pyatigor A. D. , Sotnikova V. S. , Kubankina A. A. , Novikov V. Yu. , Grigoriev Yu. V.
Published: April 2024

This paper presents the results of a spectral microanalysis of the modified surface of a polysulfone fiber after irradiation with an electron beam with an energy of 10 keV. This work is a continuation of the study on the passage of 10 keV electrons through an array formed of hollow polysulfone fibers depending on the angle of rotation of the array along the vertical axis. The analysis data showed a significant modification of the inner surface of the channel after its irradiation with electrons. We have observed that prolonged irradiation with charged particle beams of polysulfone tubes forms a dark coating on the surface layer of the channel, which can have a significant impact on the throughput and control capabilities of the channels in the field of charged particle control. Comparison of the elemental composition of the surface before and after the irradiation with a 10 keV electron beam revealed an increase in the carbon concentration in the irradiated fiber by 50 wt % and an increase in the oxygen content by 40 wt %. The amount of sulfur in irradiated fibers does not change (about 10 wt %).
On a Mathematical Model of the Diffusion of Excitons in a Semiconductor Taking into Account Their Variable Lifetime
Authors: Seregina E. V. , Stepovich M. A. , Filippov M. N.
Published: April 2024

The time dependence of the concentration of nonequilibrium minority charge carriers generated in a homogeneous semiconductor material by a sharply focused electron beam, an electron probe, after the target irradiation is described. A mathematical model is constructed for the nonstationary diffusion of charged particles generated by a low-energy electron probe in a semiconductor target in the presence of two independent recombination channels of generated charge carriers in the target material. The use of a low-energy electron probe made it possible to use a two-dimensional mathematical model of diffusion in the simulation. As an initial condition in this model, the distribution of the concentration of nonequilibrium minority charge carriers under quasi-equilibrium conditions, before turning off the electron irradiation, is used. In the presence of two independent recombination channels, the profile of the decline in the concentration of nonequilibrium minority charge carriers in the target after the electron irradiation is turned off is described by the sum of two time-dependent exponents. This approach made it possible to obtain a solution to the differential equation for two-dimensional diffusion of charge carriers, taking into account their variable effective lifetime. The practical application of the developed mathematical model is implemented for the method of time-of-flight cathodoluminescence in describing the diffusion of excitons in single-crystal gallium nitride, taking into account the dependence of the concentration of generated excitons on time.
Nanorelief of the Surface of Thin Films of Al–Mn and Al–Ni Alloys upon Ion-Assisted Deposition on Glass
Authors: Tashlykova-Bushkevich I. I. , Stoliar I. А.
Published: April 2024

The patterns of structure formation, as well as the wettability, were investigated for thin films of aluminum and Al–2.1 at % Mn and Al–1.4 at % Ni alloys on glass substrates prepared by ion beam-assisted deposition. The application of scanning probe microscopy (SPM) and scanning electron microscopy allowed characterizing nano- and micrometer-sized topographic heterogeneities on the film surfaces and studying the nature of their wettability measured by sessile drop method. Within the framework of the profile and topographic approaches for the analytical analysis of SPM images, a set of discrete roughness parameters was used, supplemented by dimensionless parameters-complexes (ψ and k) and a parameter-function of probability density of the heights and valleys of the surface nanorelief. The proposed research hybrid parameter k characterizes the shape of the irregularities of the nanorelief profile, has visibility and relates to the amplitude and roughness step. The informativity of the system of nine selected parameters for estimating the roughness and irregularity of the local structure of the film surface in the cross-section and longitudinal section was shown, which allowed not only studying numerically structural-morphological changes during aluminum doping, but also determining the quantitative relationships between the microgeometry of film surface and the deposition conditions. The effect of the initial relief of the glass substrate on the parameters of the surface irregularities of the films, which, as obtained, have the form of submicron cones and local hillocks, was revealed. The Gaussian distribution of the film nanorelief of aluminum and its alloys over the surface area was obtained, and the coating surfaces could be considered as a realization of a random normal process. The frequency distributions of the microdroplet fraction by size were lognormal. The film roughness parameters were found to correlate with the size and density of droplet fraction microparticles. It was revealed that the deposition of Al-containing films reduced the surface hydrophilicity of the film/glass substrate system. When doping aluminum, the degree of morphological heterogeneity of the film surface, as well as their wettability, decreased. The homogeneous regime of film wetting with water and its dependence on the material, morphology, and chemical composition homogeneity of the surface are discussed.
Influence of Growth Equipment Vibrations on Convective Processes during Doped Semiconductor Crystals Growth
Authors: Vlasov V. N. , Strelov V. I. , Korobeynikova E. N.
Published: April 2024

In terrestrial experiments under conditions of weak convective currents, the effect of vibrations of growth equipment on the uniformity of semiconductor doped single crystals grown by the method of directional solidification was investigated. Studies are based on theoretical calculations and experimental results on the growth of gallium-doped germanium single crystals, during the crystallization of which convective processes, including those close to microgravity conditions, were simulated at different intensities. Measurement of inhomogeneity of dopant distribution over crystal length was carried out by microthermo-e.m.f. method developed and tested by the authors. (method of operational control), which avoids, among other things, the problem of the influence of the mobility of charge carriers on the measurement results. It is shown that vibrations of growth equipment lead to increased intensity of convective processes and, accordingly, to decrease of homogeneity of dopant distribution along the crystal length. It has been found that in order to obtain highly homogeneous semiconductor crystals, both in terrestrial and microgravity conditions, the crystallization process must be carried out by controlling the thermal field without mechanically moving the samples. The greatest significant influence of vibrations will be observed for microgravity conditions, where the microgravity sensitivity of doped melts to external influences greatly increases.
Study of Temperature Effect in Aqueous Solutions of Trisiloxane Surfactants at the Interface with Titanium Oxide by Neutron Reflectometry
Authors: Gapon I. V. , Kuzmenko M. O. , Avdeev M. V. , Ivanova N. A.
Published: April 2024

The possibility of using specular neutron reflectometry to study aqueous trisiloxane solutions during the transition to the superwetting state was shown. The adsorption of trisiloxane surfactants from solution onto a moderately hydrophobic surface (oxidized titanium film) with increasing temperature up to the cloud point of the solution was considered. To clarify the role of the hydrophobic part of trisiloxane surfactant molecules in the superwetting effect, a comparison was made with solutions of a nonionic hydrocarbon surfactant with similar polyoxyethylene chains.
Investigation of the Thermo Barrier Coatings of the Y–Al–O System Using Synchrotron Radiation
Authors: Nazarov A. Yu. , Vardanyan E. L. , Maslov A. A. , Nikolaev A. A. , Ramazanov K. N. , Khusainova A. M. , Shmakov A. N.
Published: April 2024

Y–Al–O thermal barrier coating was investigated using synchrotron radiation. Y–Al–O coating was deposited on molybdenum substrate using cathodic-arc deposition with two elemental cathodes made from aluminum and yttrium respectively. Phase evolution was investigated during samples heating up to 1500°C in vacuum. It was found that as-deposited coating has amorphous structure and crystallization process take place at 1160–1170°C, no another phase transformations was observed. Qualitative phase composition of coating as well as microstresses in film were determined. The results of evaluation demonstrates lack of microstresses in obtained coating. Obtained results demonstrates a possibility of Y–Al–O coating deposition by cathodic arc deposition Arc-PVD technology, and deposited coating consist of YAlO3 (predominantly), Y2O3 oxides and YAl2 intermetallic.
New Possibilities for Measuring the Ratio of the Axial and Vector Weak Interaction Constants
Authors: Serebrov A. P. , Zherebtsov O. M. , Klyushnikov G. N. , Koptyukhov A. O. , Moroz A. R. , Murashkin A. N. , Fomin A. K.
Published: April 2024

An experiment is being developed to determine the value of λ, the ratio of the axial weak interaction constant GA to the vector constant GV, by simultaneously measuring the electron (A) and neutrino (B) asymmetries of β-decay on the same setup. The λ measurement is based on the ratio: λ = (A – B)/(A + B). Simultaneous measurements of A and B on the same setup are suggested to be carried out using ultracold neutrons stored in the magnetic field of a superconducting solenoid. The proposed method for determining λ, firstly, makes it possible to neglect the contribution of the Firtz interference term, and, secondly, eliminates the need for accurate measurement of the neutron polarization. The presented method allows us to measure the λ value with a precision of 10–4.
Modern Scanning Electron Microscopy. 1. Secondary Electron Emission
Authors: Novikov Yu. A.
Published: April 2024

The development of modern technologies, including nanotechnology, is based on application of diagnostic methods of objects used in technologies processes. For this purpose most perspective are methods realized in a scanning electron microscope. Thus one of basic methods is the measurement of linear sizes of relief structures of micrometer and nanometer ranges used in micro- and nanoelectronic. In a basis of a scanning electron microscope job the secondary electronic issue of firm body lays. However, practically all researches were spent on surfaces, which relief was neglected. The review of theoretical and experimental materials to researches of a secondary electron emission is given. Practically all known laws are checked up in experiments and have received the physical explanation. However, the application of a secondary electronic emission in a scanning electron microscopy, used in micro- both nanoelectronic and nanotechnology, requires knowledge of laws, which are shown on relief surfaces. Is demonstrated, what laws can be applied in a scanning electron microscope to measurement of linear sizes of relief structures. Is judged necessity of an influence study of a surface relief on a secondary electron emission.
Optical Properties and Structure of In2O3 Films Deposited on Al2O3 (012) Substrates by dc-Magnetron Sputtering
Authors: Tikhii A. A. , Nikolaenko Yu. M , Svyrydova K. A. , Zhikharev I. V.
Published: April 2024

The results of studies of the optical properties and structure of In2O3 films on Al2O3 (012) substrates deposited by dc-magnetron sputtering are summarized. The investigated films differ in the deposition time, substrate temperature, and the presence of additional heat treatment in air. According to X-ray diffraction measurements, these films show a reflex, which correspond to the (222) plane of the cubic modification of In2O3. Its exact position and half-width depend on the deposition time. The optical properties of the obtained films are explained by the microstructure, which is inhomogeneous in thickness and formed during the sputtering of a target with a relatively low mechanical strength. Thus, the refractive index of films deposited on substrates at room temperature increases in the direction from the substrate to the external interface. At a substrate temperature of more than 300°C, the refractive index of the films is uniform, except for a rough layer on the surface. Heat treatment reduces the number of defects in the crystal structure of the films, and leads to densification of the film material. As a result, the inhomogeneity of the refractive index disappears and the observed band gap for direct transitions decreases. The latter result from a change in the Burstein–Moss shift in consequence of the decrease of lattice defects concentration. The band gap for “indirect” transitions (that corresponds to the true value of the band gap) is insensitive to annealing.
Control of the Magnetostatic Stray Fields Using Electric Current
Authors: Tikhomirov O. A.
Published: April 2024

Possibility to control magnetic stray fields around conductive layered ferromagnet-containing systems has been analyzed. It is shown that different patterns of magnetic stray field can be realized depending on layers parameters and current. Calculation is based on the simplified model where the real stray field is approximated with that of effective magnetic charges at the sample surface. In case of in-plane magnetization the induced stray field partially screens the external one. This screening is less effective when the applied magnetic field is replaced with electric current. In case of out-of-plane magnetization the stray field is concentrated near domain walls and near sample edges where it can be extremely strong. The mechanism to control different components of the stray field via domain wall rotation by current-induced magnetic field is proposed. Numerical estimation shows that expected ratio of stray field to current is close to experimental values obtained in numerous transport measurements and usually ascribed to proximity effects (exchange interaction between carriers in adjacent layers). The proposed alternative origin of effective field should be taken into account dealing with spin Hall effect and similar spintronics problems.
Molybdenum Texture Effect on High Temperature Oxidation Resistance of Cr/Mo-Coated Zr–1Nb Alloy
Authors: Abdulmenova A. V. , Syrtanov M. S. , Kashkarov E. B. , Sidelev D. V.
Published: April 2024

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
Authors: Anikin K. A. , Zhukov A. A. , Strapolova V. N. , Apelfeld A. V.
Published: April 2024

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.
Polymethyl Methacrylate with a Molecular Weight of 107 g/mol for X-Ray Lithography
Authors: Nazmov V. P. , Varand A. V. , Mikhailenko M. A. , Goldenberg B. G. , Prosanov I. Yu. , Gerasimov K. B.
Published: April 2024

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.
Quantum Tunneling Effect on the Transverse Motion Energy Spectrum for the Channeling Positrons in the Silicon Crystal
Authors: Syshchenko V. V. , Tarnovsky A. I. , Dronik V. I. , Isupov A. Yu.
Published: April 2024

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.
Neutron Reflectometry in Superlattices with Strongly Absorbing Rare-Earth Metals (Gd, Dy)
Authors: Antropov N. О. , Kravtsov Е. А.
Published: April 2024

Polarized neutron reflectometry was used to study Dy/Gd superlattices with different ratios of Dy and Gd layer thicknesses: 1 : 1, 2 : 1, 3 : 1. It has been experimentally shown that the formation of helical magnetic ordering in Dy layers with a period incommensurate with the period of the superlattice appears as a magnetic superlattice reflection, which is forbidden for structural reasons at a ratio of the thicknesses of the Dy and Gd layers 1 : 1. Otherwise, the formation of helical magnetic ordering has little effect on the shape of the neutron reflectometry curves. Thus, the optimization of the structure of rare-earth superlattices for the neutron reflectometry experiment makes it possible to detect helical magnetic ordering in superlattices with a period incommensurate with the structural superlattice ordering.
Measurements of Electrodynamics Parameters of a Cylindrical RF-Cavity with Stainless Steel Samples
Authors: Lalayan M. V. , Lozeev Yu. Yu. , Makarov A. I. , Polozov S. M.
Published: April 2024

Stainless steel with galvanic copper coating is often used as a material for ion linear accelerators RF cavities. However, for the cavities with complex inner surfaces obtaining a uniform copper coating becomes technologically challenging. The solution might be found in manufacturing the cavity without copper coating at all, though in that case the amount of power losses in the cavity should be carefully estimated. To make such estimations the experiment was carried out, where the electrodynamic properties of a test cavity with two coupling loops were measured with the stainless steel samples placed inside it. The results of this experiment showed sufficient difference between the simulated and measured Q-factor values for the same 12Х18Н10Т sample steel grade. Thus, an assumption was made the magnetic properties of austenitic steel samples could have changed during the manufacturing process, so the magnetic permeability values for the steel samples were estimated.
Conceptual Design of a Time-of-Flight Powder Diffractometer for a Compact Neutron Source
Authors: Moskvin E. V. , Grigoryeva N. A. , Kovalenko N. A. , Grigoriev S. V.
Published: April 2024

A conceptual design of a powder diffractometer for a compact neutron source DARIA based on a linear proton accelerator is presented. The proposed concept extends the possibilities of optimizing the device performance not only by varying the diffractometer parameters, but also the neutron source parameters, such as the moderator temperature, repetition rate, and duration of neutron pulses. The results of calculating the spectrum of the target assembly for different types of moderators are presented. The efficiency of the neutron source system for increasing the neutron flux on the sample is evaluated in the McStas software package. The calculation results show the principal possibility of implementing the neutron diffraction method under conditions of limited luminosity of the compact neutron source.
Proton Injector for Compact Neutron Source DARIA Systems Optimization
Authors: Vybin S. S. , Izotov I. V. , Mironov E. A. , Palashov O. V. , Skalyga V. A.
Published: April 2024

This paper is devoted to magnetic trap and extraction system upgrade of ECR ion source GISMO to utilize it as a proton injector for linear accelerator of compact neutron source DARIA. An open permanent magnet (Nd–Fe–B) trap was designed. It was adjusted to place the extraction system inside a part of magnet with larger inner diameter. Then, the three-electrode extractor optimization was made. It was shown that the use of additional magnetic lens allows to produce the proton beam with a low divergence angle. The use of the magnetic trap and the extraction system as a part of the proton injector for DARIA project possibility was shown using computer modeling. The following steps of the proton injector creation are discussed.
Free Volume in Amorphous Alloys and Its Change under External Influences
Authors: Abrosimova G. E. , Aronin A. S.
Published: April 2024

The effect of excess free volume on the structure and crystallization of amorphous metal alloys is considered. Its change is an important characteristic of such alloys. Changes in the free volume during structural relaxation, aging, heat treatment, deformation, and irradiation are given. It is shown that the excess free volume fraction in the material depends on the alloy composition and the conditions for its production and changes under various external influences, which can contribute to both a decrease and an increase in the fraction. An increased fraction of excess free volume affects the physical properties, the evolution of the structure, and also contributes to the acceleration of the crystallization of the amorphous phase. The ability to control the free volume fraction in a sample opens up new ways to control the structure and, as a result, the properties of materials.
Low-Period Multilayered Ti/NixMoy Films with Variable Quasi-Homogeneous Structure for Neutron Reflectometry
Authors: Avdeev M. V. , Gapon I. V. , Merkel D. , Yerdauletov M. , Djanseitov D. M. , Tropin T. V.
Published: April 2024

The results of testing multilayered Ti/NixMoy heterostructures with a low period of sublayers are presented regarding the practical applicability of a quasi-homogeneous approach with varying the effective scattering length density of thin (thickness 100 nm) films in experiments on specular neutron reflectometry with a changing interface. By changing the effective scattering length density of the films, it proposed to vary the contrast between the components of complex interfaces, thus increasing the sensitivity and information content of the in situ neutron experiment. Structures with different ratios of NixMoy and Ti sublayer thicknesses were synthesized by magnetron sputtering. Based on the analysis of neutron specular reflectivity curves, a conclusion is made about the applicability of the homogeneous approximation.
Effect of the Molecular Brush Topology on the Stabilization of Silver and Selenium Nanoparticles in Aqueous Nanodispersions: Spectral and Structural-Morphological Characteristics
Authors: Valueva S. V. , Vylegzhanina M. E. , Borovikova L. N. , Ivanov I. V. , Yakimansky A. V.
Published: April 2024

Amphiphilic molecular brushes, i.e. graft copolymers (graft-CP), with a hydrophobic polyimide main chain and hydrophilic side chains of polymethacrylic acid at a high degree of polymerization m of the side chains and their grafting density, can be used as nanocontainers for the targeted delivery of drugs/agents. In this work, silver nanoparticles (Ag0) or selenium nanoparticles (Se0) in zero-valence form with a complex of unique biomedical properties were used as a loading agent. A comparative study of aqueous dispersions of Ag0 and Se0 nanoparticles stabilized by amphiphilic molecular brushes of varying topology was carried out using UV–visible spectroscopy, atomic force microscopy and transmission electron microscopy. The possibility of controlling the structural-morphological and spectral parameters of the Ag0/graft-CP and Se0/graft-CP nanostructures by changing the degree of polymerization m of side chains of the graft copolymer is shown.
Influence of the Substrate on the Photoluminescence Spectra of CaF2/Si Multilayer Structures
Authors: Velichko A. A. , Ilyushin V. A. , Krupin A. Y. , Filimonova N. I. , Rudenko I. E.
Published: April 2024

In this work, we demonstrate photoluminescence from the CaF2/Si multilayer structures formed on the surface of Si(111), Si(100), and SiO2/Si(100) substrates at ambient temperature followed by annealing. The influence of the substrate structure on the photoluminescence spectra is discussed. Studies of the photoluminescence spectra of the multilayer CaF2/Si structures have shown that the shape and position of the maxima of the photoluminescence spectra on different substrates are different, despite the fact that the structures are identical. The heterostructures differed only in the substrates, while the thicknesses and number of layers were the same. The photoluminescence spectra of the samples on the single-crystal Si(100) and Si(111) substrates are similar in the shape and have the similar wavelengths corresponding to the maximum of the photoluminescence spectra. The position of the wavelengths corresponding to the maximum of the photoluminescence spectra on the Si(100) and Si(111) single-crystal substrates correspond to the calculations obtained on the basis of the quantum confinement effect. At the same time, the shapes of the photoluminescence spectra on an amorphous silicon oxide layer differ sharply from the spectra on single-crystal substrates. The photoluminescence spectra of the samples on the amorphous SiO2/Si(100) substrates have two maxima, and the more intense spectral line is shifted to the shorter wavelengths. It is assumed that the nucleation mechanisms of the silicon nanocrystals and their subsequent crystallization during annealing on the amorphous SiO2/Si(100) substrates are radically different from the formation conditions for the silicon nanocrystals on the single-crystal substrates The different crystallographic structures of the surfaces of the three types of substrates create different conditions for the recrystallization during annealing and, therefore, lead to different properties of both the interfaces of these heterostructures and to different nanocrystalline structures of the silicon layers. Based on the obtained experimental data, a conclusion was made about the influence of the crystallographic structure of the substrates on the photoluminescence spectra.
Multilayer ZrO2/Cr Coating for Protection of E110 Zirconium Alloy from High-Temperature Oxidation
Authors: Sidelev D. V. , Ruchkin S. E. , Syrtanov M. S. , Pirozhkov A. V. , Maximov P. N.
Published: April 2024

Cr coatings with multilayer barrier composed of alternating ZrO2 and Cr layers with an individual thickness of each layer of 50 and 250 nm were prepared onto substrates made from zirconium E110 alloy using magnetron sputtering. The protective multilayer ZrO2/Cr coating on zirconium E110 alloy were studied under high-temperature oxidation in air at a temperature of 1100°C for 10, 20, 30 and 40 min. The lower rate of change in weight gain of samples having ZrO2/Cr barriers was found in comparison with samples coated by chromium during long-term oxidation tests. Diffraction measurements of samples were done under linear heating (50°С/min) in a range of temperature of 25–1250°С and next isothermal treatment for 20 min under high vacuum (10–3 Pa) using the in situ diffraction. It was found that the mutual diffusion of Cr-Zr at the interface between the protective coating having the multilayer barrier composed of alternating ZrO2 and Cr layers and zirconium alloy can be slowed down. This results in the retention of high content of α-Cr phase in the coating and, as a result, in the increase of the duration of the protective state of E110 alloy under the high-temperature oxidation in air.
Some Methods for Improving the Quality of Magnetic Force Microscopy Images
Authors: Temiryazev A. G. , Temiryazeva M. P.
Published: April 2024

Some factors affecting the quality of magnetic force microscopy images are considered. The main attention is paid to the deterioration of the quality of scans caused by contamination of the probe. It is shown that contamination can occur both during scanning and during storage of the probe. These two different sources of contamination show up differently in images, and different methods must be used to eliminate them. A likely source of probe contamination is the gel used in probe storage and shipping boxes. The magnetic coating of cantilevers can be a catalyst for a chemical reaction leading to the formation of liquid hydrocarbons. The liquid contaminants act as probe functionalizers. When the probe is moved away from the surface, mechanical bonds can be maintained between them due to the molecular chains adsorbed on the probe. Depending on the degree of pollution, the presence of such a connection can lead either to the appearance of stripes in the image of the magnetic structure, or to the complete disappearance of the magnetic contrast. A modification of the standard procedure for magnetic measurements, i.e., the introduction of an additional bounce into the two-pass technique (lift mode), makes it possible to completely eliminate the parasitic influence of this effect.
Plasma Spraying of Silicide Coatings to Protect Zirconium Alloys from Oxidation
Authors: Gnesin I. B. , Prokhorov D. V. , Gnesina N. I. , Nekrasov A. N. , Gnesin B. A. , Vnukov V. I. , Karpov M. I. , Zheltyakova I. S. , Stroganova T. S.
Published: April 2024

The work is devoted to an experimental study of the possibilities of applying a protective silicide coating on an alloy based on zirconium (E110) by atmospheric plasma spraying. Coatings based on the binary eutectic Mo5Si3 + MoSi2 were deposited on the surface of E110 alloy sheet. The features of the structure and phase composition of the coatings after deposition and their evolution as a result of isothermal annealing at a temperature of 1300°C are studied. Upon rapid cooling of silicide particles during coating, nonequilibrium phases are formed. As a result of annealing, the phase composition changes, which corresponds to the phase diagram. The kinetics of diffusion interaction between the coating and the base material has been studied. The possibility of successfully protecting a zirconium alloy from oxidation at 1100°C in air by complex deposition of a coating of molybdenum silicides has been shown for the first time. The minimum radius of curvature of the surface of the protected samples was about 1 mm.
Magnetotransport Studies of (Cd1 – xZnx)3As2 at High Pressures
Authors: Saypulaeva L. A. , Zakhvalinskii V. S. , Alibekov A. G. , Pirmagomedov Z. Sh. , Gadzhialiev M. M. , Marenkin S. F. , Ril A. I. , Kochura A. V.
Published: April 2024

Resistivity ρ, magnetoresistance Δρxx/ρ0(P) and Hall constant RH were measured in (Cd1 – xZnx)3As2 sample with х = 0.31 under the action of all-round pressure and at various temperatures in the range (80–400) K. These samples were obtained by the modified Bridgman method. The composition of the samples and their homogeneity were controlled by X-ray phase analysis and energy-dispersive X-ray spectroscopy. The results of energy dispersive X-ray spectroscopy showed that the distribution of elements in the sample is uniform. It was found that the resistivity increases with increasing temperature, and the change in ρ(T) has a metallic character. The Hall constant RH in the field decreases slightly with increasing temperature and retains a negative sign throughout the entire range under study. With increasing pressure, anomalies were observed in the baric dependences of the electrical resistivity ρ(Р), magnetoresistance Δρxx/ρ0(Р) and the Hall coefficient RH(Р). Increasing the confining pressure leads to suppression of the positive magnetoresistance. In the phase transition region, the negative magnetoresistance at a pressure Р (2.4–2.7) GPa in a field of 5 kOe is the maximum value of 1.7.
Scanning Synchrotron X-Ray Fluorescence Microanalysis for Tephrochronological Studies
Authors: Rakshun Ya. V. , Rogozin D. Yu. , Darin A. V. , Darin F. A. , Sorokoletov D. S.
Published: April 2024

On the border of China and North Korea, there is the only active stratovolcano in the eastern part of Asia – Paektusan (other names are Baitoushan, Changbaishan). It is widely known for one of the largest eruptions in the historical era, which occurred in the 10th century AD. On a volcanic activity scale, the event is rated at seven points, this is the largest eruption in the last millennium. Modern research shows that the eruption of the Paektusan volcano occurred in late autumn–winter 946 AD. This dating is supported by data obtained from the study of an ice core from North Greenland, in which traces of volcanic ash were found. At a depth of 860 mm (the age according to the calculation of annual layers is 942 AD ± 26 years), a layer 2–3 mm thick was found, which differed sharply in color and texture from the rest of the core material. Using a module of confocal X-ray microscopy, an optical section containing an anomalous layer was studied. 2D scanning with a focused beam of synchrotron radiation 20 µm in diameter was carried out. A large amount of microparticles with a high content of zirconium and yttrium was found inside the layer. The possibility of finding traces of the eruption of the Paektusan volcano is discussed.
Influence of Aluminium on the Structure and Electrical Properties of Amorphous Diamond-Like Silicon-Carbon Films
Authors: Popov A. I. , Barinov A. D. , Yemets V. M. , Zezin D. A. , Chukanova T. S. , Afanas’ev V. P. , Semenov-Shefov M. A. , Terekhov V. A. , Domashevskaya E. P. , Presnyakov M. Yu. , Shapetina M. A.
Published: April 2024

This article studies the influence of aluminium, a weak-carbide-forming metal, on phase composition, structure, and electro physical properties of amorphous diamond-like silicon-carbon films. The results of this study are compared with the influence on the same characteristics of strong-carbide-forming transition metals – titanium and hafnium. It is shown that the effects of aluminium and transition metals on the structure and properties of silicon-carbon films are fundamentally different. The addition of aluminium in a wide range of concentrations, in contrast to transition metals, does not lead to formation of a nano-crystalline phase in the films. The dependence of electrical conductivity on the aluminium concentration is smooth and monotonic, but in the case of transition metals, it has a pronounced percolation form. In addition, the absolute values of changes in electrical conductivity differ by orders of magnitude. The performed studies allowed us to conclude that the reasons for these differences are due to the interaction of metals with different chemical elements of the film. Transition metal atoms interact mainly with carbon atoms to form nanocrystals of highly conductive carbides. In contrast, aluminium atoms mainly interact with oxygen atoms and form an amorphous phase of aluminium oxide.
Formation of Zn-Containing Clusters in Implanted Si3N4 Film
Authors: Tereshchenko A. N. , Privezentsev V. V. , Firsov A. A. , Kulikauskas V. S. , Zatekin V. V. , Voronova M. I.
Published: April 2024

The results of the synthesis and study of Zn-containing clusters at the interface of a Si3N4/Si film implanted with 64Zn+ ions with a dose of 5 × 1016 cm–2 and an energy of 40 are presented. The Si3N4 film was preliminarily deposited on a silicon substrate from chemical vapor. Then, the implanted samples 10 × 10 mm in size were annealed in an oxidizing atmosphere (in air) with a step of 100°C for 1 h at each step in the temperature range 400–800°C. To study the profiles of zinc during annealing, the Rutherford backscattering method was used. The structure and composition of the film were studied using scanning electron microscopy in combination with energy dispersive spectroscopy, as well as photoluminescence. After implantation, individual clusters of metallic zinc with a size of about 100 nm or less were recorded near the surface of the Si3N4 film. It has been established that, during annealing, Zn clusters grow in the sample and the phase of metallic Zn gradually transforms into phases of its oxide ZnO and then, presumably, Zn2SiO4 silicide. After annealing at a temperature of 700°C, which is the most optimal for obtaining the ZnO phase, zinc oxide сlusters about 100 nm in size are formed in the Si3N4 film. A peak appears in the photoluminescence spectrum at a wavelength of 370 nm due to exciton luminescence in zinc oxide. After annealing at 800°C, the ZnO phase degrades and, presumably, the zinc silicide phase Zn2SiO4 is formed.
Study of Reflectivity and Microstructure of Mo/Be Multilayer Mirrors
Authors: Antysheva G. D. , Kumar N. , Pleshkov R. S. , Yunin P. A. , Polkovnikov V. N. , Chkhalo N. I.
Published: April 2024

The reflection coefficient and microstructure of Mo/Be multilayer mirrors were studied as functions of Γ, the ratio of the Mo layer thickness to the period dp. The thickness and period of the layers were studied using X‑ray diffraction (wavelength 0.154 nm). Clearly defined high-intensity Bragg reflection peaks indicate good reproducibility of layer thicknesses over the depth of the multilayer structure and high quality of interfaces. The reflectivity of the mirror at a wavelength of 11.4 nm was maximum 62% at Γ = 0.42. It sharply decreased at higher and lower values of Γ. Both Mo and Be layers at Γ = 0.42 were polycrystals, which were studied using X-ray diffraction and Raman spectroscopy, respectively. It was also found that the sizes of crystallites almost coincided with the thicknesses of the Be and Mo layers in the period.
Synergetic Effect in Multilayer Coating Systems Ni–P–W and W–C Obtained by Chemical-Catalytic Metallization and Chemical Vapor Deposition
Authors: Dushik V. V. , Ruban E. A. , Drovosekov A. B. , Shaporenkov A. A. , Rozhanskiy N. V.
Published: April 2024

The interface features of the W–C system obtained by chemical vapor deposition and Ni–P–W layers of various compositions obtained by chemical-catalytic metallization are studied. Ni–P–W layers are used as support layers for coatings of the W–C system to improve the adhesive strength of the applied coatings to steels and resistance to loads directed along the normal to the surface. The methods of scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy have been used to study the morphology, phase and elemental composition of the obtained layers, as well as phase transformations occurring in the layers during heat treatment. Mechanical tests have shown that Ni–P layers with low phosphorus content, in terms of their characteristics, demonstrate the best support properties.
Formation of Radiation Defects in Wide-Band Semiconductors Based on Gallium (Ga2O3, GaN) under Proton Irradiation
Authors: Kozlovski V. V. , Vasil’ev A. E. , Lebedev A. A. , Zhurkin E. E. , Levinshtein M. E. , Strelchuk A. M.
Published: April 2024

Using mathematical modeling of the displacement cascade in two wide-gap semiconductors based on gallium, gallium oxide (Ga2O3) and gallium nitride (GaN), the features of the generation of Frenkel pairs during the scattering of protons with energies of 8 and 15 MeV are considered. The number of displacements created not only by primary knocked-on atoms, but also by recoil atoms generated in displacement cascades is calculated for the first time. Calculations have shown that under proton irradiation of Ga2O3, for example, the fraction of vacancies in the oxygen sublattice created directly by protons is only 12%. The remaining 88% are created by recoil atoms in cascade processes. For the gallium sublattice, these fractions are 25 and 75%, respectively. Therefore, the processes of compensating the conductivity of GaN and Ga2O3 observed under proton irradiation will be determined by deep centers created not by primary knocked-on atoms, but by recoil atoms formed in displacement cascades. A comparison with experimental data is made, and the fraction of Frenkel pairs dissociating during irradiation is estimated.
The Potential of Liquid Glass Using for Smoothing the Surface of Optical Elements
Authors: Mikhaylenko М. S. , Zorina М. V. , Petrova D. V. , Pestov А. Е. , Strulya I. L. , Chkhalo N. I.
Published: April 2024

It is proposed to use “liquid glasses” of different compositions as substrates for space-based X-ray optical elements. One of the main requirements for such materials is the smallest mass and the possibility of surface treatment. Special requirements are imposed on the surface roughness, which must be less than 1 nm, and the shape accuracy should be at the level of units of nanometers. It is proposed to use a class of compounds based on alkali metal silicates or strong organic bases as a material, which allows forming the required shape and roughness, as well as providing subsequent treatment. The effect of smoothing the surface roughness of liquid glasses of three different compositions deposited on chromium and nickel films has been studied. Before and after the deposition of the structures, the roughness of all surfaces has been studied using an atomic force microscope. The roughness has been calculated using the power spectral density function (PSD function). The structures deposited on the surface, were irradiated with accelerated argon ions with an energy of 800 eV. The etch depth and effective roughness have been measured. One of the studied compositions has demonstrated a satisfactory reduction in roughness and the stability of this effect during ion etching.
Observation of Magnetic-Field-Induced Electric Polarization in Terbium Orthoferrite
Authors: Ivanov V. Yu , Kuz'menko A. M , Tikhanovskiy A. Yu , Pronin A. A , Mukhin A. A
Published: April 2024

In TbFeO3 orthoferrite at temperatures below the antiferromagnetic ordering temperature for the terbium subsystem (∼3.2 K), the electric polarization Pa(Hb) induced by a magnetic field Hb along the a axis is found. Such polarization is accompanied by anomalies related to metamagnetic (for Tb) and spin-reorientation (for Fe) transitions. At low magnetic fields |H| Hcr1 ∼ 5 kOe, the Pa(Hb) dependence exhibits a strong hysteresis and has a “butterfly” shape, while in intermediate-field magnetic configurations, |Hcr1| |H| |Hcr2| ~ 18 kOe, the sign of the polarization is determined by the sign of an applied electric field, and the Pa(Hb) dependence turns out to be nonmonotonic. A qualitative explanation of the observed effects is given in the framework of a symmetry analysis of the allowed magnetoelectric interactions in the field-induced magnetic structures.
Unconventional Fractional Quantum Hall States in a Wide Quantum Well
Authors: Dorozhkin S. I , Kapustin A. A , Fedorov I. B , Umanskiy V. , Smet Yu. Kh
Published: April 2024

A bilayer electron system that is formed in a 60-nm-wide GaAs quantum well and has a large difference of the electron densities in the layers has been studied. It has been found that, when a magnetic field is tilted from the normal to the plane of the system, integer quantum Hall effect states at the filling factors of Landau levels of 1 and 2 disappear; instead, fractional quantum Hall effect states in the interval between these filling factors appear at the filling factors νF = 4/3, 10/7, and 6/5 with odd denominators and at the filling factor νF = 5/4. Several different states can be observed under the variation of the magnetic field. The detected fractional quantum Hall effect states are interpreted as combined states with the same filling factor 1 in the layer with the higher density and with the filling factors νF – 1 in the layer with the lower density. These states are formed because of the redistribution of electrons between the layers, which occurs under the variation of the magnetic field. The appearance of the state with the filling factor νF = 5/4 with the even denominator is presumably attributed to the dominance of the interlayer electron–electron interaction over the intralayer one for electrons in the layer with the lower density.