Journal of Experimental and Theoretical Physics最新文献

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Lifshitz Transitions and Angular Conductivity Diagrams in Metals with Complex Fermi Surfaces 具有复杂费米面的金属中的利夫希茨转变和角传导图
IF 1 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2024-01-12 DOI: 10.1134/S1063776123110079
A. Ya. Maltsev
{"title":"Lifshitz Transitions and Angular Conductivity Diagrams in Metals with Complex Fermi Surfaces","authors":"A. Ya. Maltsev","doi":"10.1134/S1063776123110079","DOIUrl":"10.1134/S1063776123110079","url":null,"abstract":"<p>We consider the Lifshitz topological transitions and the corresponding changes in the galvano-magnetic properties of a metal from the point of view of the general classification of open electron trajectories arising on Fermi surfaces of arbitrary complexity in the presence of magnetic field. The construction of such a classification is the content of the Novikov problem and is based on the division of non-closed electron trajectories into topologically regular and chaotic trajectories. The description of stable topologically regular trajectories gives a basis for a complete classification of non-closed trajectories on arbitrary Fermi surfaces and is connected with special topological structures on these surfaces. Using this description, we describe here the distinctive features of possible changes in the picture of electron trajectories during the Lifshitz transitions, as well as changes in the conductivity behavior in the presence of a strong magnetic field. As it turns out, the use of such an approach makes it possible to describe not only the changes associated with stable electron trajectories, but also the most general changes of the conductivity diagram in strong magnetic fields.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 5","pages":"706 - 724"},"PeriodicalIF":1.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139465276","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}
引用次数: 0
Hydraulic Jump for Planar and Axisymmetric Flow of a Fluid Layer 流体层平面和轴对称流动的水力跳动
IF 1 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2024-01-12 DOI: 10.1134/S1063776123110110
A. D. Sukhov, A. G. Petrov
{"title":"Hydraulic Jump for Planar and Axisymmetric Flow of a Fluid Layer","authors":"A. D. Sukhov,&nbsp;A. G. Petrov","doi":"10.1134/S1063776123110110","DOIUrl":"10.1134/S1063776123110110","url":null,"abstract":"<p>We consider fluid flow with a free boundary, which is defined as a function of height from coordinate <i>x</i> with two asymptotes at positive and negative infinities (hydraulic jump). The Boussinesq approximation is used to describe the phenomenon, and an additional force is introduced. The force is chosen to depend only on the height of the surface. The problem is solved analytically without using numerical schemes. This technique is used to determine the jump surface and the acting force depending on the wave propagation coordinate.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 5","pages":"725 - 731"},"PeriodicalIF":1.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139465349","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}
引用次数: 0
Antiferromagnetic Excitonic Insulator 反铁磁励磁绝缘体
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100138
V. V. Val’kov
{"title":"Antiferromagnetic Excitonic Insulator","authors":"V. V. Val’kov","doi":"10.1134/S1063776123100138","DOIUrl":"10.1134/S1063776123100138","url":null,"abstract":"<p>The effective the two-band Hamiltonian is obtained for iridium oxides with account for strong electron correlations (SEC) and the spin–orbit interaction. The intraatomic electron correlations in iridium ions induce the formation of Hubbard fermions (HF) filling the states in the valence band. Another consequence of SEC is associated with the emergence of the antiferromagnetic (AFM) exchange interaction between HF in accordance with the Anderson mechanism. As a result, a long-range antiferromagnetic order is established in the system, and in the conditions of band overlapping, the intersite Coulomb interaction induces a phase transition to the excitonic insulator (EI) state with a long-range AFM order. The system of integral self-consistent equations, the solution to which determines the excitonic order parameter components Δ<sub><i>i</i>,</sub> <sub><i>j</i></sub>(<i>k</i>), sublattice magnetization <i>M</i>, Hubbard fermion concentration <i>n</i><sub><i>d</i></sub>, and chemical potential μ, is obtained using the atomic representation, the method of two-time temperature Green’s functions, and the Zwanzig–Mori projection technique. The symmetry classification of AFM EI phases is performed, and it is shown that in the nearest neighbor approximation, state Δ<sub><i>i</i>,</sub> <sub><i>j</i></sub>(<i>k</i>) with the <i>s</i>-type symmetry corresponds to the ground state, while the phases with the <i>d</i>- and <i>p</i>-symmetries are metastable.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"474 - 485"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569798","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}
引用次数: 0
Bragg Resonances in a Multiferroic Double-Nonlinearity Crystal 多铁性双非线性晶体中的布拉格共振
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100060
M. A. Morozova, O. V. Matveev, D. V. Romanenko, S. A. Nikitov
{"title":"Bragg Resonances in a Multiferroic Double-Nonlinearity Crystal","authors":"M. A. Morozova,&nbsp;O. V. Matveev,&nbsp;D. V. Romanenko,&nbsp;S. A. Nikitov","doi":"10.1134/S1063776123100060","DOIUrl":"10.1134/S1063776123100060","url":null,"abstract":"<p>The influence of double (electrical and magnetic) nonlinearity on the Bragg resonances of the hybrid electromagnetic-spin waves in a multiferroic crystal has been theoretically and experimentally revealed. The multiferroic crystal consists of an yttrium iron garnet layer with a periodic system of grooves on the surface and a ferroelectric strontium–barium titanate layer. A dispersion relation for the hybrid waves is obtained, and the mechanism of formation of main and hybrid band gaps, namely, suppression bands, is revealed. It is shown that taking into account the magnetic nonlinearity leads to frequency rearrangement of both band gaps and taking into account the electrical nonlinearity leads to frequency rearrangement of only the hybrid band gap. In the general case, the effects of the electrical and magnetic nonlinearities on the hybrid band gap can be compensated.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"432 - 441"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138562143","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}
引用次数: 0
Spin Transfer Torque and Nonlinear Quantum Electron Transport in Chiral Helimagnets 手性螺旋磁体中的自旋传递扭矩和非线性量子电子传输
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100126
V. V. Ustinov, I. A. Yasyulevich
{"title":"Spin Transfer Torque and Nonlinear Quantum Electron Transport in Chiral Helimagnets","authors":"V. V. Ustinov,&nbsp;I. A. Yasyulevich","doi":"10.1134/S1063776123100126","DOIUrl":"10.1134/S1063776123100126","url":null,"abstract":"<p>We construct a nonlinear theory of electric resistance of chiral helimagnets, in which the shape changes and the magnetization spiral starts rotating during the passage of electric current due to the spin transfer torque effect. It is shown that the rotation of the spin spiral under the action of the passing current, the electric resistance of the helimagnet is always lower than the resistance of a helimagnet in which the spin spiral is stationary. It is found that the current–voltage characteristic of the helimagnet in the presence of the spin transfer torque from the conduction electron system to the system of localized electrons can be essentially nonlinear. The possibility of the spin electric bistability effect in helimagnets is predicted for the situation when the spin contribution to electric resistance of a helimagnet can take two different values for the same value of the current passing through it. The possibility of realization of states with a negative differential resistance in helimagnets is demonstrated.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"422 - 431"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138561882","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}
引用次数: 0
Magnetostatic Mechanism of Chiral Symmetry Breaking in Multilayer Magnetic Structures 多层磁结构中手性对称破缺的磁静力机制
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100187
M. A. Kuznetsov, A. A. Fraerman
{"title":"Magnetostatic Mechanism of Chiral Symmetry Breaking in Multilayer Magnetic Structures","authors":"M. A. Kuznetsov,&nbsp;A. A. Fraerman","doi":"10.1134/S1063776123100187","DOIUrl":"10.1134/S1063776123100187","url":null,"abstract":"<p>It is shown that the energy of a ferromagnetic film deposited onto a paramagnetic or superconducting substrate acquires a contribution in the form of the Dzyaloshinskii–Moriya interaction. This contribution appears as a result of the magnetostatic interaction of the magnetization of the ferromagnetic film with the magnetization induced by it in a paramagnet or by the supercurrent in the superconductor and leads to the removal of the chiral degeneracy, nonreciprocity of spin waves, and the formation of chiral states such as magnetic skyrmions. Our estimates indicate the possibility of experimental observation of predicted effects.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"442 - 452"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139329164","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}
引用次数: 0
Optical Linear Dichroism in the ab-Plane of NdFe3(BO3)4 Ferroborate NdFe3(BO3)4 铁硼酸盐 ab 平面上的光学线性二色性
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100011
K. N. Boldyrev, M. Diab, I. A. Gudim, M. N. Popova
{"title":"Optical Linear Dichroism in the ab-Plane of NdFe3(BO3)4 Ferroborate","authors":"K. N. Boldyrev,&nbsp;M. Diab,&nbsp;I. A. Gudim,&nbsp;M. N. Popova","doi":"10.1134/S1063776123100011","DOIUrl":"10.1134/S1063776123100011","url":null,"abstract":"<p>The high-resolution optical absorption spectra of NdFe<sub>3</sub>(BO<sub>3</sub>)<sub>4</sub> single crystals have been recorded at temperatures from 4 to 40 K in the IR range of <i>f</i>–<i>f</i> transitions in a Nd<sup>3+</sup> ion. Light linearly polarized at different angles to the <i>C</i><sub>2</sub> axes in the basal plane has been passed along the trigonal <i>C</i><sub>3</sub> axis. Below the temperature of magnetic moment ordering into a collinear antiferromagnetic structure (<i>T</i><sub>N</sub> ≈ 30 K), dichroism, that is, the absorption versus polarization dependence, arises. The temperature and angular dependences of dichroism indicate that the magnetic moments of iron are directed along the <i>C</i><sub>2</sub> axes up to about 17 K, the number of domains with variously directed <i>C</i><sub>2</sub> axes being different. The mechanism of linear dichroism has been discussed. Below 17 K, a smooth transition to the helicoidal magnetic phase has been observed, with the collinear phase coexisting with the helicoidal one. Data presented in this article contradict the earlier concept of magnetic moments fluctuating in the low-temperature phase near the <i>C</i><sub>2</sub> axis within the ±10° interval.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"486 - 491"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569413","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}
引用次数: 0
Magnetic Properties of the Double Perovskite Sr2CrNbO6 双包晶石 Sr2CrNbO6 的磁性能
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100096
D. V. Popov, R. G. Batulin, M. A. Cherosov, I. V. Yatsyk, T. I. Chupakhina, Yu. A. Deeva, I. I. Fazlizhanov, R. M. Eremina, T. Maiti
{"title":"Magnetic Properties of the Double Perovskite Sr2CrNbO6","authors":"D. V. Popov,&nbsp;R. G. Batulin,&nbsp;M. A. Cherosov,&nbsp;I. V. Yatsyk,&nbsp;T. I. Chupakhina,&nbsp;Yu. A. Deeva,&nbsp;I. I. Fazlizhanov,&nbsp;R. M. Eremina,&nbsp;T. Maiti","doi":"10.1134/S1063776123100096","DOIUrl":"10.1134/S1063776123100096","url":null,"abstract":"<p>A double perovskite Sr<sub>2</sub>CrNbO<sub>6</sub> powder compound was studied by using X-ray diffraction, AC and DC magnetization, and ESR measurements. Two transitions in antiferromagnetically ordered regimes were observed through magnetization measurements at <i>T</i> = 5 and 2 K and were confirmed by the linear dependence of the magnetization on the applied magnetic field at these temperatures, approximations of the temperature dependence of the ESR linewidth, and AC magnetization. The zero field cooling curve was approximated by Bonner–Fisher law for quasi one dimensional chain with the exchange integral <i>J</i>/<i>k</i><sub>B</sub> = 1 K between chromium spins. An approximation of linear part of magnetic susceptibility temperature dependence was performed using Curie–Weiss law. To describe the obtained effective moment μ<sub>eff</sub> = 3.577μ<sub>B</sub>, the presence Cr<sup>3+</sup> and Cr<sup>4+</sup> ions is estimated at a respective ratio about 0.8 : 0.2.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"555 - 561"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569540","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}
引用次数: 0
Structural Disorder, Specific Heat, and Magnetic Transitions in Cu2FeBO5 Cu2FeBO5 中的结构紊乱、比热和磁性转变
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100175
Yu. S. Gokhfeld, N. V. Kazak, N. A. Bel’skaya, M. S. Molokeev, I. A. Gudim, O. A. Kondratiev, E. V. Eremin, Yu. V. Knyazev, D. A. Velikanov, S. G. Ovchinnikov
{"title":"Structural Disorder, Specific Heat, and Magnetic Transitions in Cu2FeBO5","authors":"Yu. S. Gokhfeld,&nbsp;N. V. Kazak,&nbsp;N. A. Bel’skaya,&nbsp;M. S. Molokeev,&nbsp;I. A. Gudim,&nbsp;O. A. Kondratiev,&nbsp;E. V. Eremin,&nbsp;Yu. V. Knyazev,&nbsp;D. A. Velikanov,&nbsp;S. G. Ovchinnikov","doi":"10.1134/S1063776123100175","DOIUrl":"10.1134/S1063776123100175","url":null,"abstract":"<p>Cu<sub>2</sub>FeBO<sub>5</sub> ludwigite single crystals have been grown from a solution–melt by spontaneous crystallization. Using the X-ray diffraction method, the crystal structure has been resolved in detail. Cations in sites M2, M3, and M4 have turned out to be structurally disordered. It has been found that oxygen atoms are disordered in one of five nonequivalent sites (O4). As can be seen from Mössbauer spectroscopy data, Fe<sup>3+</sup> ions occupy four nonequivalent sites with different distortions of coordination octahedra. In the temperature range 40 K ≤ <i>T</i> ≤ 300 K, the spectra represent a superposition of quadrupole doublets. Static susceptibility measurements have revealed two magnetic features at <i>T</i><sub>1</sub> = 35 K and <i>T</i><sub>2</sub> = 20 K and spin-glass effects. Specific heat measurements in the interval 4–300 K have not discovered magnetic-transition-related anomalies.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"494 - 505"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569539","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}
引用次数: 0
Magnetic Resonance in the Quasi-2D Square Lattice Easy-Plane Antiferromagnet Ba2MnGe2O7 准二维方格易平面反铁磁体 Ba2MnGe2O7 中的磁共振
IF 0.8 4区 物理与天体物理
Journal of Experimental and Theoretical Physics Pub Date : 2023-12-10 DOI: 10.1134/S1063776123100163
V. N. Glazkov, Yu. V. Krasnikova, I. K. Rodygina, M. Hemmida, M. Hirrle, H.-A. Krug von Nidda, T. Masuda
{"title":"Magnetic Resonance in the Quasi-2D Square Lattice Easy-Plane Antiferromagnet Ba2MnGe2O7","authors":"V. N. Glazkov,&nbsp;Yu. V. Krasnikova,&nbsp;I. K. Rodygina,&nbsp;M. Hemmida,&nbsp;M. Hirrle,&nbsp;H.-A. Krug von Nidda,&nbsp;T. Masuda","doi":"10.1134/S1063776123100163","DOIUrl":"10.1134/S1063776123100163","url":null,"abstract":"<p>We report results of a multi-frequency (0.8–60 GHz) electron spin resonance study of the spin dynamics in the quasi-2D square lattice antiferromagnet Ba<sub>2</sub>MnGe<sub>2</sub>O<sub>7</sub> both in antiferromagnetically ordered and paramagnetic phases. We directly observe two zero-field gaps in the excitation spectrum of the ordered phase, the larger one being due to easy-plane anisotropy, and the smaller one indicates the presence of fourth-order in-plane anisotropy probably related to the multiferroic properties of this compound. We observe effects of hyperfine interaction on the electron spin resonance spectra in the antiferromagnetically ordered state, which turns out to be comparable with in-plane anisotropy. The hyperfine field strength is found from the observed low-temperature electron spin resonance data. The spin dynamics of the paramagnetic phase is characterized by strong broadening of the ESR absorption line, which can be ascribed to the vortex dynamics of a 2D magnet.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":"137 :","pages":"542 - 554"},"PeriodicalIF":0.8,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569541","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}
引用次数: 0
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