Mn5Ge3 is a ferromagnetic hexagonal crystal promising for spintronics and magnetocalorics. A systematic study and analysis of the magnetic properties of the Mn5Ge3 thin film grown on Si(111) were performed. The magnetic anisotropy of the film is determined by the shape anisotropy and the easy magnetization axis aligned along the c axis of the crystal. The uniaxial anisotropy constant Ku fully corresponds to that for a bulk single crystal, which indicates that c axis coincides with film normal. Mn5Ge3 film demonstrates high saturation magnetization MS = 900 emu/cm3 (900 kA/m) at T = 100 K and magnetocaloric effect ΔS = 3.16 ± 0.22 J kg−1 K−1 at 300 K and B = 1.5 T. ΔS is comparable to that for multicomponent or Gd rare earth films. Furthermore, a different anisotropy of the magnetocaloric effect compared to bulk Mn5Ge3 was found, which may be related to the anisotropy of the film shape and, possibly, to the domain structure. The results obtained are promising for the design and development of magnetocaloric, spintronic, and spin-caloritronic devices on a silicon platform.

Charge transport in semiconductor devices is highly sensitive to light, which opens up wide application pros-pects. The lateral photovoltaic effect (LPE) is widely used in position sensitive detectors due to its high sensitivity to the light spot position. We report on the features of the LPE in silicon-based metal/insulator/semiconductor structures at helium temperatures. To investigate the LPE, Fe/SiO2/p-Si and Mn/SiO2/n-Si structures have been fabricated by molecular beam epitaxy. It has been found by studying the lateral photovoltage that the SiO2/Si interface plays a significant role in transport of photogenerated carriers, mainly via the interface states, which induce electron capture/emission processes at certain temperatures. The value of the photovoltage is likely affected not only by the metallic film thickness, but also by the substrate conductivity type and Schottky barrier. The effect of the magnetic field on the LPE is driven by two mechanisms. The first one is the well-known action of the Lorentz force on photogenerated carriers and the second one is shifting of the interface state energy levels. Basically, the magnetic field suppresses the contribution of the interface states to the LPE, which suggests that the interface-induced transport can be controlled magnetically.

The more correct recalculation from the measured Cherenkov light fluxes at distances of 200 (Q200) and 100 (Q100) m from the Extensive Air Shower (EAS) core to the energy of the primary particle has been developed using the results of M-C simulation by the CORSIKA code, assuming a light primary composition of cosmic rays. Using the new conversion expressions, a differential energy spectrum was obtained according to the data of the Tunka-133 array for 7 years of operation and the TAIGA-HiSCORE array for 2 years of operation.

Planar and vertical hybrid structures, which combine ferromagnetic and semiconductor layers are essential for implementation and study of spin transport phenomena in semiconductors, which is crucial for the advancement and development of spintronics. We have developed approaches for the synthesis of Fe 3 + x Si 1 – x epitaxial thin films and demonstrated the spin accumulation effect in multiterminal devices based on Fe 3 + x Si 1 – x /Si. Fe 3 + x Si 1 – x /Ge/Fe 3 Si and Fe 3 + x Si 1 – x /Ge/Mn 5 Ge 3 multilayer hybrid structures were synthesized on a Si(111) substrate, study of their structural, magnetic and transport properties were performed. The effect of synthesis conditions on the growth of epitaxial structures and on their magnetic and transport properties was discussed. The results obtained may prove valuable in the development and fabrication of spintronic devices.

Проведено исследование поведения полного содержания углекислого газа в атмосфере степных зон Алтайского края и Новосибирской области. Впервые получены количественные оценки валовой первичной продукции для исследуемых зон. Информационной основой являлись данные орбитальных карбоновых обсерваторий OCO-2 и OCO-3 по содержанию CO2 и продукт “флуоресценция хлорофилла, индуцированная солнечным светом”. Анализ данных OCO-2 проводился для периода 2014–2021 гг., результаты OCO-3 добавлены в обработку с 2019 г. Для описания сезонного цикла содержания CO2 в атмосфере использовалась эмпирическая модель, предложенная для интерпретации данных спутника GOSAT и верифицированная по результатам измерений глобальной сети наземных станций TCCON. Установлена скорость роста CO2 в атмосфере исследуемых зон. Показано, что валовая первичная продукция за счет переработки атмосферного CO2 наземной растительностью достигает максимума в летние месяцы и составляет порядка 10–12 гC/(м2 день). The purpose of this work is to establish the behaviour of the total carbon dioxide content in an atmosphere of the steppe zones of Altai krai and Novosibirsk region in 2014–2021, as well as to obtain quantitative estimates of the gross primary production using the product “Solar induced chlorophyll fluorescence” (SIF) of the orbital carbon observatories OCO-2 and OCO-3. Methods. To achieve this goal, we processed the CO 2 and SIF product content data at the orbital carbon observatories OCO-2 and OCO-3. The analysis of OCO-2 data was carried out for the period 2014–2021, the results of OCO-3 were added to processing in 2019. To describe the seasonal cycle of CO2 in the atmosphere, we used an empirical model proposed for the interpretation of the GOSAT satellite data and verified by the results of measurements of the global network TCCON. Results. It has been established that for the period under study, the growth rate of CO2 in the atmosphere of the steppe regions of Altai krai is ∼2.36±0.6 ppm/year, the amplitude of seasonal fluctuations is ∼5.0 ppm. For the steppe zones of Novosibirsk region, the growth rate of CO2 is ∼2.52±0.09 ppm/year, the amplitude of seasonal fluctuations is ∼4.8 ppm. It is shown that the average gross primary production due to the processing of atmospheric CO2 by terrestrial vegetation in the steppe ones of Altai krai and Novosibirsk region reaches a maximum in the summer months and is equal to ∼10–12 gC/( m2 day). Conclusions. Using the CO2 and SIF product content data at the OCO-2 and OCO-3 orbital carbon observatories, we carried out the study of the behavior of the total carbon dioxide content in the atmosphere of the steppe zones of Altai krai and Novosibirsk region. The quantitative estimates of gross primary production in these regions have been obtained for the first time.

В докладе представлены количественные оценки валовой первичной продукции для региона юга Западной Сибири (50º-55º с.ш., 75º-90º в.д.), полученные с использованием продукта «флуоресценция хлорофилла, индуцированная солнечным светом», орбитальных карбоновых обсерваторий OCO-2 и OCO-3. Анализ данных OCO-2 проводился для периода 2014-2021 гг., результаты OCO-3 добавлены в обработку с 2019 года. Установлено, что сток CO2 из атмосферы, обусловленный наземной растительностью, достигает максимума в летние месяцы и составляет 10-12 Гс/м2 день.

The ac transport properties of a Fe/SiO 2 / n -Si MIS structure made in the form of a Schottky diode have been studied in magnetic fields up to 9 T. A shift in the maxima of the temperature dependences of the impedance real part observed in the magnetic field is accompanied by the magnetoimpedance effect and takes place only at a certain relative orientation between the magnetic field and the surface of the sample. It has been found that the magnetoimpedance effect is related to the recharge of impurity states. Impurity state energy E s in the presence and absence of the magnetic field has been calculated. The impurity state energy is a nonlinear function of magnetic field and can be qualitatively characterized in terms of the theory of the Zeeman giant effect in diluted magnetic semiconductors. Other mechanisms of magnetic field influence on ac transport in MIS structures, specifically, on the impurity state recharge, cannot be disregarded either. This points calls for further investigation. Obtained data may provide a deeper insight into the nature of magnetoresistive effects in semiconductors and be used to design new-generation microelectronic devices.

The temperature dependence of the resistivity of titanium oxynitride TiNxOy thin films with different oxygen and nitrogen content obtained by atomic layer deposition was investigated. We found that the resistance of all films monotonically decreased with increasing temperature and varied within a wide range depending on the chemical composition and thickness of the film. The technology for obtaining a compact temperature sensor of wide range from helium to room temperature based on 40 nm thick TiN0.87O0.97 is presented. Keywords: titanium oxide-nitride, temperature sensors, thin films, atomic layer deposition, integrated circuit components.

Проведено исследование поведения полного содержания углекислого газа в атмосфере юга Западной Сибири (48º-53º с.ш., 60º-90º в.д.) по данным орбитальных карбоновых обсерваторий OCO-2 и OCO-3. Анализ данных OCO-2 проводился для периода 2014-2021 гг., результаты OCO-3 добавлены в обработку с 2019 года. Для описания сезонного цикла содержания CO2 в атмосфере региона использовалась эмпирическая модель, предложенная для интерпретации данных спутника GOSAT и верифицированная по результатам измерений глобальной сети наземных станций TCCON. Установлено, что для исследуемого периода скорость роста CO2 в атмосфере региона составляет ~2.48 млн-1/год, амплитуда сезонных колебаний ~9.3 млн-1.

A top-down nanofabrication approach involving molecular beam epitaxy and electron beam lithography was used to obtain silicon nanowire-based back gate field-effect transistors with Schottky contacts on silicon-on-insulator (SOI) wafers. The resulting device is applied in biomolecular detection based on the changes in the drain-source current (IDS). In this context, we have explained the physical mechanisms of charge carrier transport in the nanowire using energy band diagrams and numerical 2D simulations in TCAD. The results of the experiment and numerical modeling matched well and may be used to develop novel types of nanowire-based biosensors.

Herein, the AC magnetoresistance (MR) in the silicon‐on‐insulator (SOI)‐based Fe/Si/SiO2/p‐Si structure is presented. The structure is used for fabricating a back‐gate field‐effect pseudo‐metal–oxide–semiconductor field‐effect transistor (MOSFET) device. The effects of the magnetic field and gate voltage on the transport characteristics of the device are investigated. Magnetoimpedance value of up to 100% is obtained due to recharging of the impurity and surface centers at the insulator/semiconductor interface. A resistance variation of up to 1000% is found, which is caused by the voltage applied to the gate and the field effect on the band structure of the sample. Combining the magnetic and electric fields, one can either change the absolute value of the AC resistance while having the MR fixed or change the sign and character of the field dependence of the MR. The observed effects can be used in the development of magnetic‐field‐driven SOI‐based devices and high‐frequency circuits.

A silicon structure doped with Ga using ion implantation has been investigated by admittance spectroscopy. It has been established that the presence of the Ga impurity, along with the B one, in the silicon structure leads to the appearance of the second peak in the temperature dependence of the real part of the impedance (admittance). Moreover, switching-on a magnetic field parallel to the sample plane shifts the singularities in the temperature curve to the high-temperature region. This results in the manifestation of both the positive and negative magnetoresistance effect upon temperature and magnetic field variation. It has been found by the standard admittance spectroscopy analysis of the impedance data that the energy structure of the investigated sample includes two interfacial energy levels ES1(0) = 42 meV and ES2(0) = 69.4 meV. As expected, these energies are consistent with the energies of B and Ga dopants. In a magnetic field, these levels increase by 3 meV for B and 2 meV for Ga, which induces the magnetoresistance effect. It has been demonstrated that the interfacial state-induced magnetoresistance effect can be tuned by ion implantation and dopant selection.

In this paper we present the first attempt of adaptation the Random Forest (RF) machine learning algorithm to gamma/hadron separation in the TAIGA experiment (Tunka Advanced Instrument for cosmic ray physics and Gamma-ray Astronomy). The TAIGA experiment will include HiSCORE array with 120 wide-angle Cherenkov detectors on the area of 1 \(km^2\) and 5 Imaging Atmospheric Cherenkov Telescopes (IACT) on the same area. At the first stage of the analysis, only images obtained by one IACT were included in consideration. The training process occurs on samples of parameterized images obtained from Monte Carlo (MC) data for gammas and hadrons with a ‘Scaled Hillas Parameters’ standard technique. It was shown that the program effectively separates gamma-like showers, RF method does produce stable results and is robust with respect to input parameters and provides a simple control and setup of the procedure for extracting showers from gamma rays.

This study investigates the use of results from new-generation balloon-borne and satellite instruments and earthbound observatories for quantifying primary nuclei spectra in the Galactic sources. The unique data of these experiments allowed to establish new features in cosmic ray spectra in the GV–sub-PV rigidity region, make it possible to formulate an inverse approach of retrieval the spectra of primary nuclei in cosmic ray sources. We use the non-classical diffusion model of cosmic rays in the inhomogeneous Galaxy as the forward model in the inversion. The main parameters of diffusion model are self-consistently determined from experimental data. The inversion is based on the key element of the forward model solution—the presence of knee in the cosmic ray spectrum. We demonstrate that the average value of the injection index $$\gamma$$ of primary nuclei spectra in sources equals $$\gamma\sim 2.8{-}2.9$$ .

New simulation results, obtained from the chemical version of the regional climate model RegCMCHEM4, are presented for Siberian region. The verification of the chemical subsystem of the model with non-hydrostatic dynamical core is carried out using the atmospheric chemical transfer scheme CBMZ (Carbon Bond Mechanism-Z). To define chemical emissions the global RCP (Representative Concentration Pathways) emission dataset prepared by the International Institute for Applied Systems Analysis (IIASA), is used. For gas phase species, we have prepared the 6 hourly chemical boundary conditions from our modified version of the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4). Quantitative estimates of methane emission in the atmosphere of the Siberian region have been obtained.

The paper considers the behavior of total methane content in the atmosphere of Western Siberia obtained using the global chemical transport model MOZART-4 (Model for OZone And Related chemical Tracers, version 4). We discuss details of the model configuration for simulation of methane content until the end of the XXI century within the Representative Concentration Pathways (RCP4.5 and RCP8.5). Boundary conditions at the lower levels of the model (methane content in the surface air layer) was obtained using data from the Earth System Research Laboratories (ESRL) project and the results of the Atmospheric Chemistry-Transport Models (ACTM) for 2007–2010. The methane content in the stratosphere was also defining according to the ACTM results. The climate data used in MOZART-4 is based on the results of the Goddard Earth Observing System, Version 5 (GEOS-5). The modification of the boundary conditions carried out in the work made it possible to reproduce the summer and winter maximum in the annual course of CH4. These results are confirmed by satellite and aircraft observations made on the territory of Western Siberia. It was found that the total methane content in the atmosphere of the studied region (45–65 N, 60–90 E) in 2000–2020 increased with a trend of about 3.5 ± 0.2 ppb/year. In 2000–2006, there is virtually no trend. The increase of CH4 in 2007–2020 has a trend of ∼ 5.0 ± 0.2 ppb/year. The global data obtained as a result of the simulation can be used as initial and boundary conditions of the chemical version of the regional climate model RegCM-CHEM4.

The electrical injection of a spin-polarized current into silicon was demonstrated in the Fe3Si/n-Si epitaxial structure. The spin accumulation effect was studied by measuring local and nonlocal voltage signals in a specially prepared 4-terminal device. The detected effect of electrical bias on the spin signal is discussed and compared with other results reported for ferromagnet/semiconductor structures.