Pub Date : 2024-03-10DOI: 10.3103/s0027134923060164
R. E. Simakov
Abstract
The boundary value problem for a singularly perturbed system of two second-order ordinary differential equations with different powers of a small parameter at the second derivatives is considered without requiring the right-hand sides to be quasimonotonic. The specific feature of the problem is that one of the two equations of the degenerate system has a double root. It is proven that for sufficiently small values of a small parameter, the problem has a boundary layer type solution. A condition has been obtained that replaces the quasimonotonicity condition and expands the class of problems to which the results of the work are applicable.
{"title":"Reaction-Diffusion Systems with Nonlinear Sources of Different Intensities in the Case of Multiple Root without Quasimonotonicity Condition","authors":"R. E. Simakov","doi":"10.3103/s0027134923060164","DOIUrl":"https://doi.org/10.3103/s0027134923060164","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The boundary value problem for a singularly perturbed system of two second-order ordinary differential equations with different powers of a small parameter at the second derivatives is considered without requiring the right-hand sides to be quasimonotonic. The specific feature of the problem is that one of the two equations of the degenerate system has a double root. It is proven that for sufficiently small values of a small parameter, the problem has a boundary layer type solution. A condition has been obtained that replaces the quasimonotonicity condition and expands the class of problems to which the results of the work are applicable.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140098673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-10DOI: 10.3103/s002713492306005x
A. S. Gerasimov, A. K. Likhoded, V. A. Petrov, V. D. Samoylenko
Abstract
Various models of tetraquark generation in the reaction (K^{+}prightarrow T(us;bar{s}bar{s})X) are considered. The predictions for corresponding inclusive spectra were evaluated at the energies 32 and 250 GeV.
{"title":"On the Possibility of Observing Tetraquarks in the $$boldsymbol{K^{+}}$$ Beam","authors":"A. S. Gerasimov, A. K. Likhoded, V. A. Petrov, V. D. Samoylenko","doi":"10.3103/s002713492306005x","DOIUrl":"https://doi.org/10.3103/s002713492306005x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Various models of tetraquark generation in the reaction <span>(K^{+}prightarrow T(us;bar{s}bar{s})X)</span> are considered. The predictions for corresponding inclusive spectra were evaluated at the energies 32 and 250 GeV.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140100246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-10DOI: 10.3103/s0027134923060061
A. V. Isaeva, M. O. Bevzo
Abstract
In the oil and gas industry, there is growing interest in using the PC-SAFT equation of state for predicting the phase behaviour and physical properties of hydrocarbons. This article demonstrates how this equation of state can be used in combination with the direct energy minimisation algorithm of an isochoric-isothermal system for calculating vapour-liquid equilibrium parameters of hydrocarbons. The proposed approach is tested on four substances: methane, ethane, propane, and n-butane.
{"title":"Calculation of Phase Equilibria of Pure Light Hydrocarbons Using the PC-SAFT Equation of State and the Direct Energy Minimisation","authors":"A. V. Isaeva, M. O. Bevzo","doi":"10.3103/s0027134923060061","DOIUrl":"https://doi.org/10.3103/s0027134923060061","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In the oil and gas industry, there is growing interest in using the PC-SAFT equation of state for predicting the phase behaviour and physical properties of hydrocarbons. This article demonstrates how this equation of state can be used in combination with the direct energy minimisation algorithm of an isochoric-isothermal system for calculating vapour-liquid equilibrium parameters of hydrocarbons. The proposed approach is tested on four substances: methane, ethane, propane, and n-butane.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140889612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-10DOI: 10.3103/s0027134923060085
Taner Kalayci
Abstract
In this study, the magnetic, structural, and electronic properties of Pt/[Pt/Co]({}_{4})/Pt thin film was investigated both experimentally and theoretically. The effects of crystal orientation on magnetic behavior in the primitive cell were investigated via the first-principles methods. Band structures, total and partial density of states was calculated as the electronic properties. Magneto-optical Kerr effect and ferromagnetic resonance techniques were carried out to determine magnetic properties. The magnetic behavior of Pt/[Pt/Co]({}_{4})/Pt in microscopic framework is revealed by the spin asymmetry in the density of states around the Fermi level. The perpendicular magnetic anisotropy is found to be more favorable for the Pt/[Pt/Co]({}_{4})/Pt with (111) orientation. It was seen that the crystal orientation of Pt/[Pt/Co]({}_{4})/Pt has a critical role on the magnetic properties according to the band magnetism calculations.
{"title":"Investigation of the Magnetic, Structural, and Electronic Properties of Pt/[Pt/Co] $${}_{mathbf{4}}$$ /Pt Thin Film by Experimental and Theoretical Methods","authors":"Taner Kalayci","doi":"10.3103/s0027134923060085","DOIUrl":"https://doi.org/10.3103/s0027134923060085","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In this study, the magnetic, structural, and electronic properties of Pt/[Pt/Co]<span>({}_{4})</span>/Pt thin film was investigated both experimentally and theoretically. The effects of crystal orientation on magnetic behavior in the primitive cell were investigated via the first-principles methods. Band structures, total and partial density of states was calculated as the electronic properties. Magneto-optical Kerr effect and ferromagnetic resonance techniques were carried out to determine magnetic properties. The magnetic behavior of Pt/[Pt/Co]<span>({}_{4})</span>/Pt in microscopic framework is revealed by the spin asymmetry in the density of states around the Fermi level. The perpendicular magnetic anisotropy is found to be more favorable for the Pt/[Pt/Co]<span>({}_{4})</span>/Pt with (111) orientation. It was seen that the crystal orientation of Pt/[Pt/Co]<span>({}_{4})</span>/Pt has a critical role on the magnetic properties according to the band magnetism calculations.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140100252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-10DOI: 10.3103/s0027134923060139
G. E. Nikishev, N. A. Maslennikova, A. M. Tatarnikov, K. Yu. Parusov, A. A. Belinski
Abstract
Results of the simulation of the dependence of the ‘‘red leak’’ magnitude of photometric filters on various factors during star observations are presented: the colour index (V)–(R), luminosity class, magnitude of interstellar reddening, air mass, and precipitable water vapour in the Earth’s atmosphere. The error arising from the neglect of ‘‘red leak’’ in the case of filters used on the 0.6-m telescope of the SAI CMO can be up to (0.6^{m})–(0.8^{m}) for stars of late spectral types. Algorithms for the reduction of observational data for the (U) and (B) filters are presented. The results of observations of the rapid variability of two symbiotic stars CH Cyg and SU Lyn with cold components of very late spectral types are provided. For CH Cyg, rapid variability was detected on both observation dates. Taking into account the ‘‘red leak’’ effect, the amplitude of brightness changes in the (B) band was 0.10({}^{m}) on November 6, 2019 and 0.19({}^{m}) on December 15, 2022, with a characteristic variability time of about 20 min. For SU Lyn, rapid brightness variability in the (B) band on February 25, 2023 was not detected (with an accuracy of up to 0.003({}^{m})).
AbstractResults of the dependence of the 'red leak'' magnitude of photometric filters on various factors during star observations are presented: the color index (V)-(R), luminosity class, magnitude of interstellar reddening, air mass, and precipitable water vaporour in the Earth's atmosphere.对于晚光谱型恒星来说，在SAI CMO的0.6米望远镜上使用的滤光片忽略 "红漏 "所产生的误差可达(0.6^{m})-(0.8^{m})。介绍了对(U)和(B)滤光片的观测数据进行还原的算法。提供了对两颗共生恒星CH Cyg和SU Lyn的快速变率的观测结果，这两颗恒星具有非常晚光谱型的冷成分。对于 CH Cyg，在两个观测日期都探测到了快速变率。考虑到 "红漏 "效应，2019年11月6日(B)波段的亮度变化幅度为0.10({}^{m})，2022年12月15日为0.19({}^{m})，特征变化时间约为20分钟。对于SU Lyn来说，2023年2月25日的(B)波段的快速亮度变化没有被检测到（精度高达0.003({}^{m})）。
{"title":"On the Influence of ‘‘Red Leak’’ of Light Filters on the Brightness Estimates of Stars of Late Spectral Types Illustrated by the Observations of Rapid Variability of Symbiotic Stars","authors":"G. E. Nikishev, N. A. Maslennikova, A. M. Tatarnikov, K. Yu. Parusov, A. A. Belinski","doi":"10.3103/s0027134923060139","DOIUrl":"https://doi.org/10.3103/s0027134923060139","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Results of the simulation of the dependence of the ‘‘red leak’’ magnitude of photometric filters on various factors during star observations are presented: the colour index <span>(V)</span>–<span>(R)</span>, luminosity class, magnitude of interstellar reddening, air mass, and precipitable water vapour in the Earth’s atmosphere. The error arising from the neglect of ‘‘red leak’’ in the case of filters used on the 0.6-m telescope of the SAI CMO can be up to <span>(0.6^{m})</span>–<span>(0.8^{m})</span> for stars of late spectral types. Algorithms for the reduction of observational data for the <span>(U)</span> and <span>(B)</span> filters are presented. The results of observations of the rapid variability of two symbiotic stars CH Cyg and SU Lyn with cold components of very late spectral types are provided. For CH Cyg, rapid variability was detected on both observation dates. Taking into account the ‘‘red leak’’ effect, the amplitude of brightness changes in the <span>(B)</span> band was 0.10<span>({}^{m})</span> on November 6, 2019 and 0.19<span>({}^{m})</span> on December 15, 2022, with a characteristic variability time of about 20 min. For SU Lyn, rapid brightness variability in the <span>(B)</span> band on February 25, 2023 was not detected (with an accuracy of up to 0.003<span>({}^{m})</span>).</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140889305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-10DOI: 10.3103/s002713492306019x
E. V. Voronina
Abstract
The study examines the foci of the strongest earthquakes in the Russian segment of the Arctic, which have occurred over the entire period of observations, starting from 1976 to the present. The stress and strain fields have been studied through the analysis of the seismic moment tensor of the registered earthquakes. This analysis is conducted for the first time. Spatial distributions of the Lode–Nadai coefficient and the rate of seismotectonic strain have been obtained.
{"title":"Seismotectonics of the Russian Segment of the Arctic","authors":"E. V. Voronina","doi":"10.3103/s002713492306019x","DOIUrl":"https://doi.org/10.3103/s002713492306019x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The study examines the foci of the strongest earthquakes in the Russian segment of the Arctic, which have occurred over the entire period of observations, starting from 1976 to the present. The stress and strain fields have been studied through the analysis of the seismic moment tensor of the registered earthquakes. This analysis is conducted for the first time. Spatial distributions of the Lode–Nadai coefficient and the rate of seismotectonic strain have been obtained.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140889237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.3103/s0027134924700103
Abstract
The alloys studied in this work are of interest for the needs of hydrogen energy, electronics, pharmacology. The goal is to identify the regularities of the evolution of defect subsystems, which is necessary for the development of processes to improve the performance indicators of metallic systems. An analysis of the imperfections of the crystal lattice of the alloys Pd({}_{93.5})In({}_{6.0})Ru({}_{0.5}) (numerical indices—mass (%)) and Pd({}_{100-x})Pb({}_{x}) ((x=5), (8), (12), (16), (20) mass (%)) was carried out based on the results of X-ray diffraction using synchrotron radiation (SR) from the Kurchatov Research Center. An assessment of the probability of the presence in palladium-based membrane alloys of two-dimensional defects of the crystal lattice, affecting the structure-sensitive properties of materials—packing defects (PD), was conducted. The dependence of the probability of PD formation on the concentration and type of the doping element in palladium has been established.
摘要 这项工作研究的合金是氢能、电子学和药理学所需要的。其目的是确定缺陷子系统演变的规律性，这对于开发改善金属系统性能指标的工艺是必要的。对合金 Pd ({}_{93.5}) In ({}_{6.0}) Ru ({}_{0.5}）（数值指数-质量（%））和 Pd （{}_{100-x}）Pb （{}_{x}）（（x=5），（8），（12），（16），（20）质量（%））是根据库尔恰托夫研究中心使用同步辐射（SR）的 X 射线衍射结果进行的。对钯基膜合金中存在二维晶格缺陷的概率进行了评估，这种缺陷会影响材料的结构敏感特性--堆积缺陷（PD）。研究确定了堆积缺陷的形成概率与钯中掺杂元素的浓度和类型有关。
{"title":"Determining the Presence of Packing Defects in Palladium-Based Alloys by X-Ray Diffraction Method","authors":"","doi":"10.3103/s0027134924700103","DOIUrl":"https://doi.org/10.3103/s0027134924700103","url":null,"abstract":"<span> <h3>Abstract</h3> <p>The alloys studied in this work are of interest for the needs of hydrogen energy, electronics, pharmacology. The goal is to identify the regularities of the evolution of defect subsystems, which is necessary for the development of processes to improve the performance indicators of metallic systems. An analysis of the imperfections of the crystal lattice of the alloys Pd<span> <span>({}_{93.5})</span> </span>In<span> <span>({}_{6.0})</span> </span>Ru<span> <span>({}_{0.5})</span> </span> (numerical indices—mass <span> <span>(%)</span> </span>) and Pd<span> <span>({}_{100-x})</span> </span>Pb<span> <span>({}_{x})</span> </span> (<span> <span>(x=5)</span> </span>, <span> <span>(8)</span> </span>, <span> <span>(12)</span> </span>, <span> <span>(16)</span> </span>, <span> <span>(20)</span> </span> mass <span> <span>(%)</span> </span>) was carried out based on the results of X-ray diffraction using synchrotron radiation (SR) from the Kurchatov Research Center. An assessment of the probability of the presence in palladium-based membrane alloys of two-dimensional defects of the crystal lattice, affecting the structure-sensitive properties of materials—packing defects (PD), was conducted. The dependence of the probability of PD formation on the concentration and type of the doping element in palladium has been established.</p> </span>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.3103/s0027134924700036
Abstract
Iron chalcogenides intercalated with alkali metal atoms attract the attention of physicists due to their unusual natural phase segregation, where superconducting clusters form at the boundaries of the antiferromagnetic phase. In this work, using photoelectron spectroscopy, we discovered an unusual effect that presumably arises due to this phase segregation. We studied temperature dependences of the photoelectron spectra of Se 3d, Fe 3p, and the valence band at temperatures above and below (T_{c}approx 27) K of the compound (K({}_{0.8})Na({}_{0.2}))({}_{0.8})Fe({}_{1.8})Se({}_{2}) with substitution of alkali metal atoms. A strong temperature dependence was found for both the valence band and the core levels: we observed a significant broadening of the spectra, which monotonically decreased with increasing sample temperature under cyclical temperature change. We believe that this broadening is associated with the appearance of volume charges in the dielectric matrix, leading to the band bending. Moreover, the shape of the potential that arises under the surface of this compound was restored, and an estimate was obtained for the relative amount of the superconducting phase. These results will help to better understand the physical processes occurring in this compound.
摘要 与碱金属原子插层的铁铬化物因其不寻常的自然相分离而吸引了物理学家的注意，在反铁磁相的边界会形成超导簇。在这项研究中，我们利用光电子能谱发现了一种可能由这种相分离引起的不寻常效应。我们研究了化合物（K ({}_{0.8}) Na ({}_{0.2}) ）在高于和低于 (T_{c}approx 27) K 的温度下 Se 3d、Fe 3p 和价带的光电子能谱的温度依赖性。Fe ({}_{1.8}) Se ({}_{2}) 随着碱金属原子的替代。我们发现价带和核级都有很强的温度依赖性：我们观察到光谱有明显的展宽，在循环温度变化下，随着样品温度的升高，展宽单调地减小。我们认为，这种拓宽与介质基体中出现的体积电荷有关，导致了能带弯曲。此外，我们还还原了该化合物表面下产生的电势形状，并估算出了超导相的相对数量。这些结果将有助于更好地理解这种化合物中发生的物理过程。
{"title":"Anomalous Band Bending in the (K $${}_{mathbf{0.8}}$$ Na $${}_{mathbf{0.2}}$$ ) $${}_{mathbf{0.8}}$$ Fe $${}_{mathbf{1.8}}$$ Se $${}_{mathbf{2}}$$ Superconductor","authors":"","doi":"10.3103/s0027134924700036","DOIUrl":"https://doi.org/10.3103/s0027134924700036","url":null,"abstract":"<span> <h3>Abstract</h3> <p>Iron chalcogenides intercalated with alkali metal atoms attract the attention of physicists due to their unusual natural phase segregation, where superconducting clusters form at the boundaries of the antiferromagnetic phase. In this work, using photoelectron spectroscopy, we discovered an unusual effect that presumably arises due to this phase segregation. We studied temperature dependences of the photoelectron spectra of Se 3<em>d</em>, Fe 3<em>p</em>, and the valence band at temperatures above and below <span> <span>(T_{c}approx 27)</span> </span> K of the compound (K<span> <span>({}_{0.8})</span> </span>Na<span> <span>({}_{0.2})</span> </span>)<span> <span>({}_{0.8})</span> </span>Fe<span> <span>({}_{1.8})</span> </span>Se<span> <span>({}_{2})</span> </span> with substitution of alkali metal atoms. A strong temperature dependence was found for both the valence band and the core levels: we observed a significant broadening of the spectra, which monotonically decreased with increasing sample temperature under cyclical temperature change. We believe that this broadening is associated with the appearance of volume charges in the dielectric matrix, leading to the band bending. Moreover, the shape of the potential that arises under the surface of this compound was restored, and an estimate was obtained for the relative amount of the superconducting phase. These results will help to better understand the physical processes occurring in this compound.</p> </span>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.3103/s0027134924700048
Abstract
In the study, numerical results of simulations for the deposition process of a complex optical coating are presented, utilizing broadband monitoring of this process in the case where the noise level in the measured transmittance coefficient has a nonuniform distribution across the wavelength. The influence on the accuracy of control data at the edges of the measured wavelength range, where the error in the transmittance coefficient is maximal, is investigated. It is shown that the removal of some data at the edges of the range almost does not change the self-compensation factor of the errors in the deposition process, while the average norm of the error vector in the layer thicknesses significantly decreases. Thus, for the first time, it is demonstrated that taking into account the effect of error self-compensation in broadband control opens the possibility of a reasonable choice of the optimal spectral range for practical optical control.
{"title":"Consideration of the Distribution of Noise Level by Wavelength in Broadband Control of the Optical Coating Deposition Process","authors":"","doi":"10.3103/s0027134924700048","DOIUrl":"https://doi.org/10.3103/s0027134924700048","url":null,"abstract":"<span> <h3>Abstract</h3> <p>In the study, numerical results of simulations for the deposition process of a complex optical coating are presented, utilizing broadband monitoring of this process in the case where the noise level in the measured transmittance coefficient has a nonuniform distribution across the wavelength. The influence on the accuracy of control data at the edges of the measured wavelength range, where the error in the transmittance coefficient is maximal, is investigated. It is shown that the removal of some data at the edges of the range almost does not change the self-compensation factor of the errors in the deposition process, while the average norm of the error vector in the layer thicknesses significantly decreases. Thus, for the first time, it is demonstrated that taking into account the effect of error self-compensation in broadband control opens the possibility of a reasonable choice of the optimal spectral range for practical optical control.</p> </span>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.3103/s0027134924700176
Abstract
Composite films of (Cd({}_{3})As({}_{2}))({}_{100-X})(MnAs)({}_{X}) on silicon and sitall substrates with Mn concentration of 5.8–16.4 at (%) were obtained by vacuum-thermal evaporation. The structural properties of the films were investigated by X-ray phase analysis and scanning electron microscopy. Magneto-optical properties were studied using the transverse Kerr effect (TKE) method in the energy range of 0.5–4.0 eV in magnetic fields up to 3 kOe at temperatures of 20–300 K. In the geometry of the transverse Kerr effect, the spectral, field, and temperature dependences of TKE were obtained. Analysis of experimental data showed that at Mn contents more than 12.9 at (%) the films contain the (alpha^{primeprime})-phase of the topological Dirac semimetal Cd({}_{3})As({}_{2}) in the form of large granules, as well as ferromagnetic MnAs granules. The Curie temperature of the films depends on their Mn content and is lower than that of bulk MnAs samples. At Mn contents in the film of 5.8 and 6.4 at (%), no magneto-optical response was detected, indicating the formation of a superparamagnetic state or a spin glass state at low Mn concentrations. At an Mn content in the film of 9.9 at (%), a significant change in magneto-optical spectra was observed, indicating the formation of MnAs nanoclusters and partial dissolution of Mn in the Cd({}_{3})As({}_{2}) matrix.
Abstract Composite films of (Cd ({}_{3}) As ({}_{2}) )通过真空-热蒸发法在硅和sitall基底上获得了锰浓度为5.8-16.4的（{}_{100-X}）（MnAs）复合薄膜。通过 X 射线相分析和扫描电子显微镜研究了薄膜的结构特性。利用横向克尔效应（TKE）方法研究了在 20-300 K 温度下、磁场高达 3 kOe 的 0.5-4.0 eV 能量范围内的磁光特性。对实验数据的分析表明，当 Mn 含量超过 12.9%时，薄膜含有拓扑狄拉克半金属 Cd ({}_{3}) As ({}_{2}) 的 (α^primeprime}) -相，以大颗粒的形式存在，同时还含有铁磁性 MnAs 颗粒。薄膜的居里温度取决于其锰含量，并且低于块状 MnAs 样品的居里温度。当薄膜中的锰含量为 5.8 和 6.4 时，没有检测到磁光响应，这表明在低锰浓度下形成了超顺磁态或自旋玻璃态。当薄膜中的锰含量为 9.9 时，磁光光谱发生了显著变化，表明形成了锰砷纳米团簇，锰部分溶解在镉（{}_{3}）砷（{}_{2}）基体中。
{"title":"Magneto–Optical Kerr Spectroscopy of (Cd $${}_{boldsymbol{3}}$$ As $${}_{boldsymbol{2}}$$ ) $${}_{boldsymbol{100-X}}$$ (MnAs) $${}_{boldsymbol{X}}$$ Composites","authors":"","doi":"10.3103/s0027134924700176","DOIUrl":"https://doi.org/10.3103/s0027134924700176","url":null,"abstract":"<span> <h3>Abstract</h3> <p>Composite films of (Cd<span> <span>({}_{3})</span> </span>As<span> <span>({}_{2})</span> </span>)<span> <span>({}_{100-X})</span> </span>(MnAs)<span> <span>({}_{X})</span> </span> on silicon and sitall substrates with Mn concentration of 5.8–16.4 at <span> <span>(%)</span> </span> were obtained by vacuum-thermal evaporation. The structural properties of the films were investigated by X-ray phase analysis and scanning electron microscopy. Magneto-optical properties were studied using the transverse Kerr effect (TKE) method in the energy range of 0.5–4.0 eV in magnetic fields up to 3 kOe at temperatures of 20–300 K. In the geometry of the transverse Kerr effect, the spectral, field, and temperature dependences of TKE were obtained. Analysis of experimental data showed that at Mn contents more than 12.9 at <span> <span>(%)</span> </span> the films contain the <span> <span>(alpha^{primeprime})</span> </span>-phase of the topological Dirac semimetal Cd<span> <span>({}_{3})</span> </span>As<span> <span>({}_{2})</span> </span> in the form of large granules, as well as ferromagnetic MnAs granules. The Curie temperature of the films depends on their Mn content and is lower than that of bulk MnAs samples. At Mn contents in the film of 5.8 and 6.4 at <span> <span>(%)</span> </span>, no magneto-optical response was detected, indicating the formation of a superparamagnetic state or a spin glass state at low Mn concentrations. At an Mn content in the film of 9.9 at <span> <span>(%)</span> </span>, a significant change in magneto-optical spectra was observed, indicating the formation of MnAs nanoclusters and partial dissolution of Mn in the Cd<span> <span>({}_{3})</span> </span>As<span> <span>({}_{2})</span> </span> matrix.</p> </span>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140598085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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