bluuebunny/crossref_metadata_2025 huggingface dataset:
Влияние относительного содержания металлической компоненты в диэлектрической матрице на образование и размеры нанокристаллов кобальта в пленочных композитах Co-=SUB=-x-=/SUB=-(MgF-=SUB=-2-=/SUB=-)-=SUB=-100-x-=/SUB=-
Authors: Домашевская Э.П. , Ивков С.А. , Ситников А.В. , Стогней О.В. , Козаков А.Т. , Никольский А.В.
Published: January 2019

AbstractThe influence of relative content of a metal component on the phase composition and substructure of Co_ x (MgF_2)_100 – _ x in a wide range of x = 16–63 at % is studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy. The layers of nanocomposite with a micron thickness have been obtained by the ion-beam sputtering of the target in the argon environment. The results reveal that the relative metal cobalt content in the MgF_2 dielectric matrix strongly affects the phase composition and substructure of nanocomposites. With a lower content of cobalt, it is in the amorphous state in the form of clusters in the MgF_2 nanocrystalline matrix. An increase of cobalt content to x = 29 at % on a sitall substrate and to x = 42 at % on a glass substrate in the X-ray amorphous MgF_2 dielectric matrix leads to the formation of cobalt nanocrystals with a hexagonal crystallographic system, whose sizes are on the order of 10 nm. These are predominately oriented in the basis plane of the (001) hexagonal lattice of α-Со. A further increase of cobalt content to c = 59 at % enlarges the α-Со nanocrystals to ~20 nm with retaining the same orientation. In accordance with a fine structure analysis of XPS spectra of Со 2 p and О 1 s , cobalt is strongly oxidized on the surface of all the composites; only on the surface of samples with a low content of Co is X‑ray amorphous cobalt found in a metallic state along with cobalt oxide. The IR spectra of these samples with the lowest metal phase content exhibit the pronounced modes from the nanocrystalline MgF_2 dielectric phase.
Возможные механизмы формирования бейнитных колоний
Authors: Разумов И.К.
Published: January 2019

AbstractThe possible mechanisms of bainitic transformation in steels are discussed. According to the known models of the growth of Widmanstatten ferrite, an acicular shape of bainitic lathes is due to anisotropy in the surface energy. However, the lath replication mechanisms in upper and lower bainite presumably differ from each other. Upper bainite results from the diffusion-controlled transformation, at which the pearlitic autocatalysis due to the formation of cementite at the interface with ferrite takes place. Lower bainite is formed at a smaller temperature via the diffusionless mechanism, when the branching of precipitates or the autocatalysis of lathes can be provided by a decrease in the system energy due to the disposition of structural defects at the interfaces of precipitates, so the existence of a characteristic lath size is energetically stipulated (Weissmüller effect). The combined effect of different autocatalysis mechanisms leads to a variety of possible bainite modifications.
К вопросу о влиянии вакансий на характеристики металла. Работа выхода и поверхностная энергия
Authors: Погосов В.В.
Published: January 2019

AbstractWithin the density functional method, a simple method for determining the dependence of the work function of electrons and specific surface energy of the metal on the relative density of internal vacancies $${{c}_{{v}}}$$ is proposed. Preserving the style of the stabilized jellium model, the preliminarily calculated volume shift of the conductivity zone bottom ε^(0) ∝ $${{c}_{{v}}}$$ in a specific homogeneous metal is introduced into a one-dimensional functional as the zero-point energy. Using the quantity $${{c}_{{v}}}$$ as a small parameter, linear corrections to the abovementioned quantities are found. The expansion coefficients are expressed in terms of characteristics of a defectless metal. Calculations for Na and Al are carried out by the Kohn–Sham method. Temperature dependences of Al characteristics have been constructed in the thermodynamic limit.
Влияние гидрирования на магнитострикцию и магнитокалорический эффект в монокристалле гадолиния
Authors: Терешина И.С. , Политова Г.А. , Четырбоцкий В.А. , Терешина-Хитрова Е.А. , Пауков М.А. , Андреев А.В.
Published: January 2019

AbstractThe gadolinium single crystal obtained by the Czochralski method was hydrogenated to the composition GdH_0.15, which corresponds to a metal–hydrogen solid solution (α phase). The magnetostriction and magnetocaloric effect were measured for both the initial and hydrogenated samples. It is found that the hydrogen atoms in the hexagonal lattice of gadolinium can affect the magnitude and sign of the magnetostriction constants and cause the anisotropy of the magnetocaloric effect. The main mechanisms responsible for the observed effects are discussed.
Метод расчета критического тока неоднородных сверхпроводящих пленок
Authors: Безотосный П.И. , Гаврилкин С.Ю. , Дмитриева К.А. , Лыков А.Н. , Цветков А.Ю.
Published: January 2019

AbstractA method for calculating the critical current of an inhomogeneous superconducting film (plate) in different external magnetic fields has been proposed. The superconducting properties are changed by varying the coherence length and London penetration depth over the thickness. The coherence length is maximum at the center of the plate and decreases upon approaching its boundaries and the London depth, on the contrary, is minimum at the center of the plate and increases toward its boundaries. Using the proposed approach, the magnetic field dependences of the critical current on the external magnetic field for the cases of nonuniform and uniform distributions of the superconducting properties over the film thickness have been calculated and compared. It has been established that at the nonuniform distribution of the superconducting properties the critical current of the plate is higher than at the uniform distribution at the same external magnetic fields. This is due to the fact that the order parameter is redistributed over the inhomogeneous plate thickness in such a way that the superconducting state becomes more stable against the current and magnetic field. It has been shown that the vortex-free Meissner state in inhomogeneous films is maintained at higher fields than in homogeneous films. The greater the film nonuniformity, the higher the stability of the Meissner state against an external magnetic field.
Выявление поверхностных состояний в топологических изоляторах Bi-=SUB=-2-x-=/SUB=-Sb-=SUB=-x-=/SUB=-Te-=SUB=-3-y-=/SUB=-Se-=SUB=-y-=/SUB=- по магнитотранспортным измерениям
Authors: Сизов В.Е. , Борисов В.И. , Кузнецов П.И. , Ткач Ю.Я.
Published: January 2019

AbstractIn this paper, we studied the effect of the magnetic field and temperature on conductivity of Bi_2 ‒ _ x Sb_ x Te_3 – _ y Se_ y topological insulators of different composition to identify electronic surface states in these films. The experimental data can be explained based on the model with two types of charge carriers. Thermoactivation conductivity, electron or hole, is observed in the film bulk depending on the sample composition while metal-like electronic states are found on the surface. The noticeable contribution of surface topological states to the total conductivity opens up the possibility of studying them.
Электрические свойства пленок металлоорганических перовскитов
Authors: Ершова А.М. , Овезов М.К. , Щербаков И.П. , Алешин А.Н.
Published: January 2019

AbstractThe electrical properties of the films of organometallic perovskites CH_3NH_3PbBr_3 and CH_3NH_3PbI_3 were studied. Current–voltage characteristics for the CH_3NH_3PbBr_3 and CH_3NH_3PbI_3 samples were measured in a temperature range of 300–80 K, from which the temperature dependences of resistivity ρ( T ) having characteristic points of inflection in a range of 160–240 K were determined. The activation energies of charge carriers prior to and after points of inflection were determined. It is assumed that the observed features in the temperature dependences of resistivity (temperature at the points of inflection) correlate with the temperatures of tetragonal-to-orthorhombic phase transitions for two studied organometallic perovskites (CH_3NH_3PbBr_3 and CH_3NH_3PbI_3).
Индуцированные магнитным полем спин-модуляционные переходы в эпитаксиальных плeнках BiFeO-=SUB=-3-=/SUB=- с ориентацией (001)
Authors: Кулагин Н.Е. , Попков А.Ф. , Соловьёв С.В. , Звездин А.К.
Published: January 2019

AbstractAlterations in the ground state of thin (001) films of a BiFeO_3 (BFO)-type multiferroic in a magnetic field are studied theoretically, with changes in the energy of induced anisotropy taken into account. The anisotropy vs. field phase diagrams identifying the stability regions of homogeneous antiferromagnetic states and the regions of emergence of spatially modulated antiferromagnetic states are constructed for three mutually orthogonal orientations of applied magnetic field. We show that, as the magnetic field decreases, the transformation of a homogeneous phase into a spatially modulated state occurs at the instability point of the homogeneous state via gradual emergence of the conical phase that transforms into a planar cycloid with the decreasing magnetic field. A multiferroic film grown on a (001) substrate develops considerable anisotropy of the energy of spatially modulated state, depending on the modulation orientation. Meanwhile, cycloids with different orientations undergo the transitions from incommensurate phase into the homogeneous state differently: either the conical cycloid is formed followed by its collapse into the homogeneous state or an unlimitedly growing domain of the homogeneous phase is formed within the flat cycloid. Examples of field-induced changes in magnetization, with changes in spin states taken into account, are provided. These results are of value in practical applications of multiferroic strain engineering.
Особенности фокусировки спиновых волн в кристаллах EuO и EuS
Authors: Бахарев С.М. , Савченко С.П. , Танкеев А.П.
Published: January 2019

AbstractSpecificities of spin wave focusing in EuO and EuS crystals are studied. It is shown that spin wave focusing is absent in the long-wave approximation: it is observed only for wave vectors in the second half of the Brillouin zone ( aq $$ \gtrsim $$ π, where a is the lattice constant and q is the magnitude of the wave vector). It was found that, for EuO and EuS crystals, the directions of spin wave focusing differ due to the different signs of the exchange integrals responsible for the exchange interaction of the magnetic moment with the second neighbors. The directions along which a magnon caustic is formed are determined.
Магнитная анизотропия многослойных гетероструктур [(Co-=SUB=-41-=/SUB=-Fe-=SUB=-39-=/SUB=-B-=SUB=-20-=/SUB=-)-=SUB=-x-=/SUB=-(SiO-=SUB=-2-=/SUB=-)-=SUB=-100-x-=/SUB=-/Bi-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=-]-=SUB=-47-=/SUB=-
Authors: Безверхний А.И. , Таланцев А.Д. , Калинин Ю.Е. , Ситников А.В. , Никитенко В.A. , Коплак О.В. , Дмитриев О.С. , Моргунов Р.Б.
Published: January 2019

AbstractMagnetic anisotropy values are obtained for [(Co_41Fe_39B_20)_ x (SiO_2)_100 – _ x /Bi_2Te_3]_47 heterostructures consisting of SiO_2 alternating layers, CoFeB nanoparticles distributed in them, and Bi_2Te_3 layers with ferromagnetic resonance and magnetometry. The heterostructures have anisotropy of ~10^6 erg/cm^3, which orients the magnetic moment in films plane. The films are not solid, but they disintegrate into CoFeB nanoparticles with an average diameter of 5 nm during deposition, which corresponds to the blocking magnetization temperature of ~30 K during their saturation magnetization of M _ S = 720 emu/cm^3. The relationship between anisotropy constant and thickness of the layers of the heterostructures is nonmonotonic due to competition between surface and bulk anisotropies of the ferromagnetic granules, which the films are made of.
Размерный эффект в нанокомпозитах на основе молекулярного сегнетоэлектрика бромида диизопропиламмония
Authors: Барышников C.B. , Милинский А.Ю. , Чарная E.B. , Егорова И.В.
Published: January 2019

AbstractWe present the results of studies of the dielectric properties of nanocomposites based on Al_2O_3 oxide films with a pore size of 330 and 60 nm with particles of an organic ferroelectric diisopropylammonium bromide (C_6H_16BrN, DIPAB) introduced into the pores, aimed at determining the size dependences of phase transition parameters. A shift in the phase transition to low temperatures and diffusion of the transition are found, which become more significant for smaller pores. A broadening of the temperature hysteresis of the dielectric constant of nanocomposites during the phase transition was also observed. The decrease in the phase transition temperature in nanocomposites with DIPAB nanoparticles is consistent with theoretical models of the size effects on the structural phase transition.
Структурные и электрические характеристики двухслойных тонких пленок Bi-=SUB=-4-=/SUB=-Ti-=SUB=-3-=/SUB=-O-=SUB=-12-=/SUB=-/(Ba,Sr)TiO-=SUB=-3-=/SUB=-, осажденных на кремниевую подложку методом высокочастотного распыления при повышенных давлениях кислорода
Authors: Анохин А.С. , Бирюков С.В. , Головко Ю.И. , Мухортов В.М.
Published: January 2019

AbstractThe 400–450-nm-thick Bi_4Ti_3O_12 thin films with various orientations of crystallites with respect to a normal to the (100)Si substrate plane have been studied. It is established that the crystallite orientation can be controlled by varying the composition of the 4-nm-thick Ba_ x Sr_1 – _ x TiO_3 sublayer. The use of Ba_0.4Sr_0.6TiO_3 as a sublayer leads to the growth of the Bi_4Ti_3O_12 film in the single-crystal state with plane (001) parallel to the substrate plane and with a monoclinic distortion of the crystal structure. The Ba_0.8Sr_0.2TiO_3 sublayer is shown to lead to the formation of four crystallite orientations: (111), (117), (100), and (110) and two groups of domains in the Bi_4Ti_3O_12 film; the first group with the polarization direction p-erpendicularly to the substrate and the second group with the polarization directed in the angular range 45.2°–57° with respect to a normal to the substrate. It is shown that, in the Bi_4Ti_3O_12 film with the Ba_0.8Sr_0.2TiO_3 sublayer, the polarization is directed to the substrate and is switched to new stable state with the polarization direction from the substrate when applying an external voltage higher than a critical one (4 V).
Образование дислокационных пар в гетероструктуре Ge/GeSi/Si(001)
Authors: Болховитянов Ю.Б. , Гутаковский А.К. , Дерябин А.И. , Соколов Л.В.
Published: January 2019

AbstractIn the Ge/LTGe/GeSi/Si(001) heterostructures, the GeSi buffer layer remains pseudomorphic in a certain range of the heterostructure parameters and growth regimes, while the Ge film is completely relaxed owing to the edge dislocation network at the Ge/GeSi interface. It has been experimentally shown that, along with edge dislocations, dislocations with the Burgers vectors of the a _0〈100〉-type form. Their formation is caused by the reaction of 60° dislocations with a unidirectional screw component. In this case, if during the buffer layer relaxation the edge dislocations split with the formation of an edge-type dislocation complex, in which the 60° dislocations remained bound, the dislocations with the Burgers vectors a _0〈001〉 split into two independent 60° dislocations.
Механизм влияния размера нанокристаллов на параметры кривых псевдоупругой и термоупругой деформации сплавов с эффектом памяти формы
Authors: Малыгин Г.А.
Published: January 2019

AbstractThe data available in the literature on the influence of the nanocrystal sizes of alloys with the shape memory effect on the parameters of the curves of their pseudoelastic and thermoelastic deformation are analyzed in the framework of the theory of diffuse martensitic transitions (DMT). The peculiarity of the DMT theory is that it is based on both thermodynamic and kinetic relationships that make it sensitive to the alloy structure on the mesoscopic scale. This enables one to state the functional dependence of the parameter of the martensitic deformation of the nanocrystals on the size of their cross section D . As a result of the analysis, it is found that the coefficient of the strain (martensitic) hardening and the hysteresis of the pseudoelastic strain curves of submicrocrystals of the Ni_54Fe_19Ga_27 are changed with D by law 1/ D ^2. The temperature range ( M _ s – M _ f ) of the martensitic transition in TiNi alloy nanocrystals is changed by analogy law. These dependences are results of the constrained displacement of dislocations of the phase transformation by transverse sizes of the crystal. A kinetic mechanism of the appearance of the critical nanocrystal size D _ k is established; the transition of austenite to martensite does not occur at transverse crystal sizes smaller than the critical size.
Нестационарный электрохимический отклик на прерывистую деформацию Портевена-Ле Шателье алюминий-магниевого сплава
Authors: Шибков А.А. , Денисов А.А. , Гасанов М.Ф. , Золотов А.Е. , Желтов М.А.
Published: January 2019

AbstractIt has been established that the Portevin–Le Chatelier effect in the AlMg6 aluminum–magnesium alloy deformed in an aqueous medium is accompanied by an intermittent electrochemical response, such as the negative jumps of the electrode potential of the sample, which occur simultaneously with the jumps of the mechanical stress on the deformation curve. Statistical and fractal analyses of the stepwise component of the electrode potential indicate the presence of long-term correlations in the structure of the electrochemical response, which are typical for the state of self-organized criticality. A possible mechanism of the appearance of jumps of the electrode potential, which is associated with the dynamics of deformation bands, is discussed.
Динамическая модель упруго-пластического нормального столкновения сферической частицы с полупространством с учетом адгезионного взаимодействия в зоне контакта
Authors: Ляшенко Я.А.
Published: January 2019

AbstractThe problem of a collision of a spherical homogeneous particle with a half-space is solved numerically. The coefficient of the normal velocity restitution is calculated as a function of the initial velocity in the presence of the mechanical energy dissipation due to plastic deformations and adhesion interaction between the surfaces of contacting bodies. The strain hardening effect is taken into account using the criterion of nonlocal plasticity introduced before. The study is carried out in dimensionless parameters, which makes it universal. The analytical expression is found for the critical initial velocity above which a plastic deformation starts. The simulation results agree well with the available experimental data.
Димерная самоорганизация примесных ионов эрбия в синтетическом форстерите
Authors: Зарипов Р.Б. , Мингалиева Л.В. , Тарасов В.Ф. , Жариков Е.В. , Субботин К.А. , Лис Д.А.
Published: January 2019

AbstractThe electron paramagnetic resonance spectra of impurity trivalent erbium ions in synthetic forsterite single crystals (Mg_2SiO_4) have been studied by the electron paramagnetic resonance method in the X and Q frequency bands. It is found that erbium ions predominantly substitute for magnesium ions in crystallographic position M1 that is characterized by the inversion symmetry of the crystal field. In this case, a pronounced effect of dimer self-organization of erbium ions during the crystal growth takes place; the effect is manifested in the fact that the concentration of erbium dimer associates consisting of two closely spaced ions bound by the spin– spin interaction is several orders of magnitude higher than the concentration of dimer associates that form randomly at a statistical distribution of impurity ions in the forsterite crystal lattice. The directions of the main magnetic axes and the parameters of the effective spin Hamiltonian describing the magnetic characteristics of impurity erbium centers have been determined.
Определение параметров эффекта Яна-Теллера в примесных центрах из ультразвуковых экспериментов: приложение к кристаллу ZnSe : Ni-=SUP=-2+-=/SUP=-
Authors: Сарычев М.Н. , Жевстовских И.В. , Аверкиев Н.С. , Берсукер И.Б. , Гудков В.В. , Суриков В.Т.
Published: January 2019

AbstractThe earlier developed methodology of ultrasonic investigation for determining the parameters of the Jahn–Teller effect (JTE) in impurity centers in crystals is further developed in application to Ni^2+ impurities in ZnSe : Ni^2+. For all normal modes propagating along the [110] axis, the temperature dependences of the attenuation of ultrasound are measured in the frequency range 25–165 MHz. At a temperature of about 13 K, for all these modes, attenuation peaks are observed, which indicate the presence of local distortions of both trigonal and tetragonal types. Following the previously developed method, it is shown that these anomalies of attenuation are caused by the relaxation transitions between equivalent local distortions induced by the JTE at the Ni^2+ centers. In the tetrahedral environment of selenium, this ion is in the threefold degenerate ground electron state ^3 T _1, in which three types of the JTE can be realized. The data of ultrasonic experiments indicate the realization of the T ⊗ ( e + t _2) problem, in which the potential energy surface has four equivalent minima of the trigonal type, slightly deformed toward tetragonal saddle points. The trigonal vibronic constants, the stabilization energies of the trigonal minima, and the activation energy of the barriers between them are ev-aluated.
Динамика решеток и барическое поведение фононов в модельных сегнетоэластиках Hg-=SUB=-2-=/SUB=-Br-=SUB=-2-=/SUB=-
Authors: Рогинский Е.М. , Крылов А.С. , Марков Ю.Ф.
Published: January 2019

AbstractRaman spectra of Hg_2Br_2 model improper ferroelastic crystals have been investigated in a wide range of high hydrostatic pressures. Baric dependences of the phonon frequencies have been obtained; of greatest interest are the observed soft mode originating from the slowest TA _1 acoustic branch at the Brillouin zone boundary ( X point) of the tetragonal phase and the anomalous behavior of this mode. In the ferroelastic phase spectra, the ignition of the second acoustic TA _2 from the same point has also been detected and its baric behavior has been studied. Under sufficiently high pressures, splitting of doubly degenerate phonons with the E _ g symmetry has been observed and explained. The parameters of the Grüneisen constants have been determined from the baric dependences of the phonon frequencies and discussed.
Влияние дейтерирования на фазовые переходы в диоксотетрафториде ванадия
Authors: Богданов Е.В. , Погорельцев Е.И. , Горев М.В. , Молокеев М.С. , Флеров И.Н.
Published: January 2019

AbstractThe crystals of (ND_4)_3VO_2F_4 with a high degree of deuteration (~87%) have been grown and a significant (~1.5%) increase in the unit cell volume has been detected. The decrease in the chemical pressure leads to a change in the sequence of phase transitions due to wedging-out of one of the rhombic phases observed in (NH_4)_3VO_2F_4. The thermal physical studies have been carried out and the entropies, deformations, and pressure coefficients related to structural transformations have been determined. The T – p phase diagram has been built and the pressure and temperature boundaries of crystal phase stability have been determined. The dielectric studies demonstrate a nonferroelectric nature of the phase transitions in (ND_4)_3VO_2F_4. The experimental and model entropies are compared. Based on the decrease in the entropy as a result of deuteration, a hypothesis on significant but not limited anharmonism of vibrations of ammonia tetrahedral corresponding to the disordering is proposed.
Calculation of the T-P phase diagrams for the halogenomethane compounds (CCl-=SUB=-4-n-=/SUB=-Br-=SUB=-n-=/SUB=-, n=0, 1, 2, 4) using the mean field theory -=SUP=-*-=/SUP=-
Authors: Yurtseven H. , Isik S.B. , Kilit Dogan E.
Published: January 2019

AbstractThe T – P phase diagrams of the halogenomethane compounds (CCl_4 – _ n Br_ n , n = 0, 1, 2, 4) are calculated using a mean field model. By expanding the free energy in terms of the order parameters for the transitions of the liquid (L), rhombohedral (R), face-centered cubic (FCC) and monoclinic (M) phases in those compounds, the phase line equations are derived and they are fitted to the experimental data from the literature. This method of calculating the T – P phase diagram is satisfactory to explain the T – P measurements for the halogenomethane compounds and it can also be applied to two-component systems.
Особенности фазообразования TbBO-=SUB=-3-=/SUB=- при изотермических отжигах
Authors: Шмытько И.М.
Published: January 2019

AbstractDetailed X-ray studies of changes in the structure of terbium orthoborate TbBO_3 in the course of successive high-temperature isothermal annealing of the initial mixture in the form of an amorphous precursor and in the form of a homogenized mixture of microcrystalline Tb_7O_12 and B_2O_3 powders have been carried out. It is shown that the formation of TbBO_3 crystals in both cases occurs through the formation of intermediate two-phase states. Particularly, the triclinic high-temperature ν-TbBO_3 phase is formed already at the first crystallization stages (about 600°C) almost simultaneously with the equilibrium vaterite modification of TbBO_3 (sp. gr. P 63/ mmc ) during low-temperature annealing of an amorphous precursor, which transforms into the vaterite modification at an annealing temperature of 850°C. The phase of monoclinic terbium trioxoborate TbB_3O_6 is formed at the first stages of phase formation (about 800°C) almost simultaneously with the vaterite phase when the feedstock is annealed in the form of a homogenized mixture of microcrystalline Tb_7O_12 and B_2O_3 powders. It also transforms into the vaterite modification at an annealing temperature of 950°, which is preserved up to the highest annealing temperatures in the experiment (1200°C). A hypothetical explanation of the formation of such two-phase states during low-temperature annealing of the feedstock and their disappearance at higher annealing temperatures is proposed.
Неравновесные диффузионные фазовые превращения в сплавах, обусловленные миграцией границ зерен и дислокаций
Authors: Разумов И.К. , Горностырев Ю.Н. , Ермаков А.Е.
Published: January 2019

AbstractThe main scenarios of nonequilibrium diffusional transformations induced by moving defects (dislocations, grain boundaries) in alloys under severe plastic deformation are considered. It has been shown that the phase state locally changes in the area of a defect where thermodynamic properties of alloy are locally changed, and the attained state is frozen after the displacement of a defect due to the difference between the rates of bulk diffusion and diffusion on a defect. For this reason, an alloy shifts from the state of its thermodynamic equilibrium under treatment, thus different nonequilibrium states, such as the disordering of alloy, the dissolution of equilibrium phase precipitates, the appearance of nonequilibrium phases, and the formation of regular structures, are possible depending on the type of the system. These effects may take place if the treatment of an alloy is performed at moderate temperatures, when diffusion is frozen in the bulk and rather active on defects. The phenomena of phase and structural instability developing under severe plastic deformation at moderate temperatures are considered within the framework of the proposed model.
Влияние флуктуаций на образование выделений вторых фаз на границах зерен
Authors: Львов П.Е. , Светухин В.В.
Published: January 2019

AbstractBased on the free energy density functional method (modified Cahn–Hillard–Cook equation), the formation kinetics of secondary phases in binary alloys is considered in the presence of composition fluctuations and with inclusion of the grain boundaries influences. It is revealed that the existence of grain boundaries and the fluctuations at the initial stage of the phase transition can lead to the appearance of anomalous growth rate of the average precipitate size due to a competition of various decomposition mechanisms.
Компьютерное моделирование структуры и механических свойств слоев силицена на графите при движении иона лития
Authors: Галашев А.Е. , Иваничкина К.А.
Published: January 2019

AbstractThe molecular dynamics method is applied to study structural and mechanical effects appearing during the lithium ion motion in a dc electric field along a planar channel formed by perfect silicene sheets and sheets containing vacancy-type defects. Mono-, di-, tri-, and hexavacancies of rather densely and uniformly filled silicene sheets are arranged one above the other on a graphite substrate. The times of Li^+ ion passage through silicene channels with various gaps are determined. The construction of Voronoi polyhedra and truncated polyhedrons, whose centers coincide with the moving ion position allowed revealing the structural features inherent to the two-dimensional layered structure. The nature of stresses appearing in silicene sheets most critical to ion motion over the channel is determined.
Получение, структура и диэлектрические характеристики монокристаллов и тонких пленок Sr-=SUB=-0.61-=/SUB=-Ba-=SUB=-0.39-=/SUB=-Nb-=SUB=-2-=/SUB=-O-=SUB=-6-=/SUB=-
Authors: Павленко А.В. , Ивлева Л.И. , Стрюков Д.В. , Ковтун А.П. , Анохин А.С. , Лыков П.А.
Published: January 2019

AbstractThe structure, lattice dynamics, and dielectric characteristics of Sr_0.61Ba_0.39Nb_2O_6 (SBN-61) single crystals and SBN-61/(001)MgO thin films have been studied. The analysis of temperature and frequency dependences of permittivity and dielectric loss tangents in a range of 10–500 K for a SBN-61 crystal has allowed one to establish the phase transition temperatures. The SBN-61/(001)MgO films are found to possess the tetragonal symmetry, characteristic of a SBN-61 crystal, but their lattice parameters are different from the latter.
Особенности локальной динамики и ориентационного состояния жесткоцепных жидкокристаллических полимеров
Authors: Рыжов В.А. , Жиженков В.В. , Квачадзе Н.Г.
Published: January 2019

AbstractProton magnetic resonance (PMR) spectra and terahertz IR spectra of Vectra A950 fibers and granules and Armos fibers before and after heat treatment were obtained and analyzed in order to understand the molecular mobility mechanisms that ensure the self-organization and restructurization of these rigid-chain liquid-crystal polymers, as well as their similarity and difference. It is shown that large-scale thermal (quasi-segmental) mobility in such LC polymers is due to the reptation of macromolecules with respect to each other and the conformational transitions necessary for the motion of chains in them are the result of random accumulation of displacements that occur during local bending and torsional-vibrational movements in the links of polymer chains according to the Bresler–Frenkel mechanism.
Светоизлучающие полевые транзисторы на основе композитных пленок полифлуорена и нанокристаллов CsPbBr-=SUB=-3-=/SUB=-
Authors: Алешин А.Н. , Щербаков И.П. , Кириленко Д.А. , Матюшкин Л.Б. , Мошников В.А.
Published: January 2019

Abstract—Light-emitting organic field-effect transistors (LE-FETs) on the basis of composite films that consist of perovskite nanocrystals (CsPbBr_3) embedded in a matrix of conjugated polymer—polyfluorene (PFO)—have been obtained, and their electrical and optical properties have been investigated. Output and transfer current-voltage characteristics (I-Vs) of FETs based on PFO : CsPbBr_3 films (component ratio 1 : 1) have a slight hysteresis at temperatures of 100–300 K and are characteristic of hole transport. The hole mobility is ∼3.3 and ∼1.9 cm^2/(V s) at the modes of the saturation and low fields, respectively, at 250 K and reaches ∼5 cm^2/(V s) at 100 K. It has been shown that the application of pulsed voltage to LE-FETs based on PFO : CsPbBr_3 can reduce the ionic conductivity and provide electroluminescence in this structure at 300 K.
Влияние деформации на энергетический спектр и спектр оптического поглощения фуллерена C-=SUB=-20-=/SUB=- в модели Хаббарда
Authors: Силантьев А.В.
Published: January 2019

Abstract —Anticommutator Green’s functions and energy spectra of fullerene C_20 with the I _ h , D _5 d , and D _3 d symmetry groups have been obtained in an analytical form within the Hubbard model and static fluctuation approximation. The energy states have been classified using the methods of group theory, and the allowed transitions in the energy spectra of fullerene C_20 with the I _ h , D _5 d , and D _3 d symmetry groups have been determined. It is also shown how the energy levels of fullerene C_20 with the I _ h symmetry group are split with the symmetry reduction.
Влияние азотного допирования и механического напряжения на адсорбционную способность графдиена
Authors: Долинский И.Ю. , Гришаков К.С. , Прудковский В.С.
Published: January 2019

AbstractThe quantum chemical simulation of adsorption of atomic hydrogen on pristine and nitrogen-doped graphdienes has been performed. The preferential sites, adsorption on which is most energetically beneficial, are indicated. The nitrogen presence is shown to substantially increase the adsorption capacity of the sheet. A capacity of the nitrogen-doped graphdiene to be reversibly stretched by 4% under action of external mechanical stress is demonstrated. A mechanical stretching is found to enable the control of the adsorption properties of pristine and also doped graphdienes.
Влияние химической модификации поверхности углеродных нанотрубок на их теплопроводность
Authors: Савин А.В. , Савина О.И.
Published: January 2019

AbstractAn effect of partial chemical modification of the surface of a single-walled carbon nanotube on its thermal conductivity is studied. Numerical simulation of heat transfer showed that partial hydrogenation (fluorination) of a nanotube (addition of hydrogen and fluorine atoms from its outer side) can lead to more than a tenfold decrease in thermal conductivity. When the length of the nanotube increases, its thermal conductivity increases in proportion to the logarithm of the length, whereas the proportionality coefficient decreases with an increase in density of hydrogen or fluorine atoms attached. A thermal conductivity reduction coefficient does not depend on the length of the nanotube, but depends on temperature (the lower the temperature, the stronger the decrease) and density of the attached atoms p . When p < 0.25, an increase in density monotonically decreases the thermal conductivity. A decrease is maximum, when density p is 0.25. If only one half of the nanotube is hydrogenated, this half has a lower thermal conductivity. Such a nanotube becomes anisotropic and can be used as a heat transfer rectifier with no more than two percent rectification efficiency.
Оптические свойства спироида C-=SUB=-300-=/SUB=-
Authors: Ястребов С.Г. , Чекулаев М.С. , Siklitskaya A.
Published: January 2019

AbstractCalculation results of the electronic spectrum of carbon nanospiroid C_300 are presented. The π-electron structure of the spiroid is calculated using the strong coupling method, in which the matrix element of the exchange interaction of neighboring electrons (the resonance integral) is considered as being dependent on the local curvature of the spiroid surface. The optical absorption coefficient is calculated in the framework of the Tautz model and the result is compared with experimental and astrophysical observational data. The calculated and experimental data are in good agreement.
Столкновение детонационных волн в пузырьковых средах
Authors: Сычев А.И.
Published: January 2019

AbstractThe oncoming collisions of detonation waves, generated in bubbly media, is studied in the present paper while determining the critical conditions of collisions initiated in bubbly media, as well as the structure and parameters of detonation waves. The structure and properties of post-detonation waves, which are wave perturbations arising upon collisions of bubbly detonation waves, are also examined.
Эрозионное воздействие микроструктурированного канала искры на поверхность плоского медного электрода
Authors: Тренькин А.А.
Published: January 2019

AbstractUsing a 3D optical profilometer, an erosion spot on the surface of a plane copper electrode has been studied. The spot arises under the action of the microstructured channel of a spark discharge initiated in atmospheric pressure air in a point–plane gap. It has been found that such spots are aggregations of microcraters. The shapes and sizes of microcraters have been determined.
Влияние структурных факторов на прочность и электропроводность объемных наноструктурных медных сплавов
Authors: Чембарисова Р.Г. , Александров И.В. , Ямилева А.М.
Published: January 2019

AbstractThe structural parameters ensuring high strength and low electrical resistance have been analyzed in Cu–Cr alloys exposed to severe plastic deformation (SPD) and aging. Specific resistance and strength characteristics have been modeled for a Cu–0.5 wt % Cr alloy with a nanostructure state caused by SPD. A comparison of modeling data with experimental values reveals the validity of the approach chosen for describing the above states. The formation of nanostructure states with high strength and low electrical resistance is shown to be due to simultaneous effects depending on the treatment conditions of materials.
Гетероструктура SmS/SiC и термовольтаический эффект в ней
Authors: Каминский В.В. , Лебедев А.О. , Соловьев С.М. , Шаренкова Н.В.
Published: January 2019

AbstractA heterostructure based on single-crystal SiC and a polycrystalline SmS thin film has been studied. In the temperature interval 300–456 K, the thermovoltaic effect has been measured in the structure, the amount of which reaches ~12 mV at 456 K. It has been shown that the amount of this effect correlates with its concentration model developed earlier.
Удельные сопротивления и тензорезистивные характеристики кристаллов твердых растворов системы TlInSe-=SUB=-2-=/SUB=--CuInSe-=SUB=-2-=/SUB=-
Authors: Умаров С.Х. , Нуритдинов И. , Ашуров Ж.Ж. , Халлоков Ф.К.
Published: January 2019

AbstractThe concentration dependences of the resistivities and tensosensitivity factors of Ti_1 –_ x Cu_ x InSe_2 alloys from TlInSe_2–CuInSe_2 system have been studied in concentration interval x = 0–0.1. It has been found that the concentration characteristics are linear in the range of solid solution existence ( x = 0–0.025) and rapidly change outside this range.
Микроскопия поверхности кремния, имплантированного ионами серебра высокими дозами
Authors: Воробьев В.В. , Рогов А.М. , Осин Ю.Н. , Нуждин В.И. , Валеев В.Ф. , Эйдельман К.Б. , Табачкова Н.Ю. , Ермаков М.А. , Степанов А.Л.
Published: January 2019

AbstractLow-energy ( E = 30 keV) Ag^+ ions have been implanted into single-crystalline Si wafers (c-Si) with an implantation dose varying from 1.25 × 10^15 to 1.5 × 10^17 ions cm^–2 and an ion beam current density varying from 2 to 15 μA/cm^2. The surface morphology of implanted wafers has been examined using scanning electron microscopy, transmission electron microscopy, and atomic force microscopy, and their structure has been studied by means of reflection high-energy electron diffraction and elemental microanalysis. It has been shown that for minimal irradiation doses used in experiments, the surface layer of c-Si experiences amorphization. It has been found that when the implantation dose is in excess of the threshold value (~3.1 × 10^15 ions cm^–2), Ag nanoparticles uniformly distributed over the Si surface arise in the irradiated Si layer. At a dose exceeding 10^17 ions cm^–2, a porous Si structure is observed. In this case, the Ag nanoparticle size distribution becomes bimodal with coarse particles localized at the walls of Si pores.
Температурная дисперсия диэлектрических характеристик композитов на основе полиэтилена и наноглин Na-=SUP=-+-=/SUP=- монтмориллонита
Authors: Иманова С.Р. , Гасанли Ш.М. , Сафарзаде У.М.
Published: January 2019

AbstractThe temperature dispersion of dielectric properties of polyethylene-based composites and nanoclays of the Na^+-montmorillonite type is studied. It was found that as a result of the heating–cooling cycle, the dielectric characteristics of samples take on new values, which are preserved for some time. It is assumed that this effect is due to thermally stimulated processes of redistribution of charges at the filler–matrix boundary and their accumulation in deeper traps and, as a consequence, emergence of nonequilibrium states of the medium.
Морфология поверхности и структура плазменных покрытий
Authors: Лепешев А.А. , Карпов И.В. , Ушаков А.В. , Зеер Г.М. , Демин В.Г. , Дорожкина Е.А. , Карпова О.Н. , Федоров Л.Ю. , Шайхадинов А.А. , Брунгардт М.В. , Гончарова Е.А. , Иртюго Л.А.
Published: January 2019

AbstractSpecific features of the structure formation in rapidly quenched high-cobalt alloy coatings formed by plasma sputtering have been investigated. The structural state of the investigated coatings has been identified by the X-ray diffraction technique. The sequence and kinetics of structural transformations occurring in the specified time-temperature heating regimes have been examined using differential thermal analysis. It has been established that heat generation and crystallization temperature depend on the conditions of formation of bulk amorphous coatings.
Моделирование детектора видимого и ближнего инфракрасного электромагнитного излучения на искусственном алмазе
Authors: Кукушкин В.А.
Published: January 2019

AbstractA method for calculation of the I – V characteristic is proposed for a detector of visible and near-IR electromagnetic radiation based on artificial diamond with allowance for vertical flow of electric current. The method can be used when the free-path length of carriers in diamond is less than the scale of variations in the concentration of carriers. The method is used to determine the following detector characteristics: the dependence of current on voltage, distribution of carrier concentration, and electric potential for a particular variant of a photodetector based on polycrystalline diamond film consisting of nanosized single crystals doped with boron.
Морфология и электронные свойства наноразмерных структур Si, созданных на поверхности CaF-=SUB=-2-=/SUB=-
Authors: Умирзаков Б.Е. , Ашуров Р.Х. , Донаев С.Б.
Published: January 2019

AbstractThe surface morphology, crystal structures, and band-energy parameters have been studied for nanofilms and regularly arranged nanoscale Si phases with a thickness of 1–2 nm. The bandgap thickness of nanocrystalline Si phases with 2–3 single layers is found to be ~1.4 eV.
Структурные и магнитные свойства систем Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-/Ge-p/Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-/Co
Authors: Кобяков А.В. , Турпанов И.А. , Патрин Г.С. , Руденко Р.Ю. , Юшков В.И. , Косырев Н.Н.
Published: January 2019

AbstractThe Al_2O_3/Ge- p /Al_2O_3/Co system with an Al_2O_3 buffer layer deposited by ion-plasma sputtering has been experimentally investigated. The dependences of the magnetic properties of cobalt on the rate of its deposition by ion-plasma sputtering and rate of deposition of preceding layers have been established. It is shown that the technique used to obtain buffer layers can significantly reduce the surface roughness of the next layers. The obtained buffer layers can be used as artificial substrates for growing heterostructures with tunnel junctions.
Акустооптическая коммутация волоконно-оптических каналов
Authors: Антонов С.Н.
Published: January 2019

AbstractAn acousto-optic commutator of fiber-optic channels based on a ТеО_2 two-coordinate deflector has been proposed and realized. The commutator yields switching of optical radiation from a single output waveguide into a two-dimensional input matrix of waveguides, or vice versa, switching from any matrix waveguide into a single output one. The main interrelated parameters have been obtained. It has been established that the commutator has a short response time of 2–10 μs, yields up to several hundreds of switching channels, low insertion losses of 2–5 dB, and a considerable inter-channel isolation from –35 to –60 dB. Experiments were performed for the output matrix containing 19 waveguides. The channel multiplexing operating mode of this commutator has been demonstrated, which is simultaneous transmission of a signal from the output waveguide into a given number of waveguides of the input matrix.
Нелинейное затухание и нелинейный фазовый набег интенсивных спиновых волн в экранированных ферритовых пленках
Authors: Козин А.Э. , Устинов А.Б.
Published: January 2019

AbstractWe analyze for the first time nonlinear damping and nonlinear phase shift of intense surface spin waves in screened yttrium–iron garnet films. Nonlinear damping coefficients are determined using the phenomenological model of spin wave propagation in such films. It is found that nonlinear phase shift in screened films is a weak effect as compared with free films and amounts to tens of degrees. At the same time, nonlinear damping in screened films is comparable with the corresponding value for free films. It is shown that for micrometer-thick films, the losses introduced upon an increase of power to 15 dBm become larger by 2–5 dB.
Анизотропия поверхностной энергии и работы выхода электрона IIВ металлов
Authors: Шебзухова И.Г. , Арефьева Л.П.
Published: January 2019

AbstractOn the basis of electron-statistical method of calculation of the surface energy of metals, a technique for estimating the electron work function of hexagonal and rhombohedral metallic crystals has been developed. This technique relates surface energy to work function and can thus be applied to estimate the surface energy of crystal faces from experimental data for a work function. Computations have been made for cadmium, zinc, and mercury macrocrystals. The temperature and orientation dependences of both quantities have been constructed. Our results are in good agreement with literature experimental data.
Исследование схемы селективной фотоионизации -=SUP=-177-=/SUP=-Lu
Authors: Дьячков А.Б. , Горкунов А.А. , Лабозин А.В. , Миронов С.М. , Цветков Г.О. , Панченко В.Я. , Фирсов В.А.
Published: January 2019

AbstractThe hyperfine structure of transitions in the three-step scheme 5 d 6 s ^22 D _3/2–5 d 6 s 6 p ^4 F $$_{{5/2}}^{^\circ }$$ –5 d 6 s 7 s ^4 D _3/2– (53 375 cm^–1) $$_{{1/2}}^{^\circ }$$ of lutetium ionization is studied for ^175Lu, ^176Lu, and ^177Lu isotopes using the photoionization laser spectroscopy method. Values of the magnetic dipole ( A ) and electric quadrupole ( B ) interaction constants are determined, as well as the energies, the isotope shifts, and the radiative lifetimes for the 5 d 6 s 7 s ^4 D _3/2 and (53 375 cm^–1) $$_{{1/2}}^{^\circ }$$ levels.
Катодолюминесценция ZnSe : Fe в средней инфракрасной области спектра
Authors: Чукичев М.В. , Чегнов В.П. , Резванов Р.Р. , Чегнова О.И. , Калинушкин В.П. , Гладилин А.А.
Published: January 2019

AbstractThe dependences of the integral intensity and kinetics of mid-IR cathodoluminescence (CL) of Fe:ZnSe crystals on an iron concentration varying from 0.01 to 14 wt % are studied in the temperature range from 78 to 300 K. It is found that the maximum mid-IR CL intensity in Fe:ZnSe is observed at an Fe concentration of about 2 wt % at room temperature and 0.8–1 wt % at liquid nitrogen temperature. A further increase in iron concentration leads to a decrease in the CL decay time.