Pub Date : 2023-12-01DOI: 10.1134/s1063776123120026
Abstract
The article by R. M. Feshchenko (J. Exp. Theor. Phys. 136, 406 (2023)) is devoted to an important issue concerning general properties of electromagnetic field pulses and contains, in particular, critical remarks on our publications (R. M. Arkhipov et al. Quant. Electronics 50, 801 (2020); R. Arkhipov et al., Laser Field Lett. 19, 043001 (2022), and M. V. Arkhipov et al., JETP Lett. 115, 1 (2022)). We reply to these critical remarks and indicate a number of inaccuracies in the aforementioned article.
摘要 R. M. Feshchenko 的文章(J. Exp. Theor.Phys. 136, 406 (2023))专门讨论了有关电磁场脉冲一般特性的重要问题,特别是对我们的出版物(R. M. Arkhipov et al.Quant.Quant. Electronics 50, 801 (2020);R. Arkhipov et al.19, 043001 (2022),以及 M. V. Arkhipov 等人,JETP Lett.115, 1 (2022)).我们对这些批评意见进行了回复,并指出了上述文章中的一些不准确之处。
{"title":"Comment to the Article “On the Time Integral of Electromagnetic Field” by R.M. Feshchenko (J. Exp. Theor. Phys. 136, 406 (2023))","authors":"","doi":"10.1134/s1063776123120026","DOIUrl":"https://doi.org/10.1134/s1063776123120026","url":null,"abstract":"<span> <h3>Abstract</h3> <p>The article by R. M. Feshchenko (J. Exp. Theor. Phys. <strong>136</strong>, 406 (2023)) is devoted to an important issue concerning general properties of electromagnetic field pulses and contains, in particular, critical remarks on our publications (R. M. Arkhipov et al. Quant. Electronics <strong>50</strong>, 801 (2020); R. Arkhipov et al., Laser Field Lett. <strong>19</strong>, 043001 (2022), and M. V. Arkhipov et al., JETP Lett. <strong>115</strong>, 1 (2022)). We reply to these critical remarks and indicate a number of inaccuracies in the aforementioned article.</p> </span>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139579363","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 : 2023-11-01DOI: 10.1134/s1063776123110067
Abstract
Exact analytic expressions are derived for the spectrum and wavefunctions of electrons in a monolayer of transition metal dichalcogenides in crossed electric and magnetic fields. The electric field dependence of interband transition intensity is calculated. The valley selectivity of interband absorption considerably depends on the electric field and can reverse its sign multiply upon an increase in this field.
{"title":"Light Absorption in Dichalcogenides of Transition Metals in Crossed Fields","authors":"","doi":"10.1134/s1063776123110067","DOIUrl":"https://doi.org/10.1134/s1063776123110067","url":null,"abstract":"<span> <h3>Abstract</h3> <p>Exact analytic expressions are derived for the spectrum and wavefunctions of electrons in a monolayer of transition metal dichalcogenides in crossed electric and magnetic fields. The electric field dependence of interband transition intensity is calculated. The valley selectivity of interband absorption considerably depends on the electric field and can reverse its sign multiply upon an increase in this field.</p> </span>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462227","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 : 2023-11-01DOI: 10.1134/s1063776123110158
Abstract
The influence of the competition of single-ion anisotropy and easy-plane anisotropy on the magnetic properties of the multilayer structure Co/Cu/Co is investigated. The peculiarities of the influence of anisotropy effects are revealed both in the vicinity of critical temperature Tc and in the low-temperature range T( ll )Tc. The magnetic properties of the multilayer structure are numerically simulated using the anisotropic Heisenberg model. In the vicinity of Tc, easy-plane anisotropy is shown to exert a predominant influence on the magnetic properties of the structure as compared to the influence of single-ion anisotropy. In the low-temperature range, the switching of the magnetic state of the ferromagnetic film in an external field leads to the appearance of specific features in hysteresis effects due to the competition of two types of magnetic anisotropy. The magnetic structure exhibits a size-induced transition from the behavior caused by easy-plane anisotropy to the behavior caused by single-ion anisotropy. The revealed size-induced transition is accompanied by a spin-flop effect.
{"title":"Influence of the Effects of Competition of Various Types of Anisotropy on the Critical Behavior of Magnetic Multilayer Structures","authors":"","doi":"10.1134/s1063776123110158","DOIUrl":"https://doi.org/10.1134/s1063776123110158","url":null,"abstract":"<span> <h3>Abstract</h3> <p>The influence of the competition of single-ion anisotropy and easy-plane anisotropy on the magnetic properties of the multilayer structure Co/Cu/Co is investigated. The peculiarities of the influence of anisotropy effects are revealed both in the vicinity of critical temperature <em>T</em><sub><em>c</em></sub> and in the low-temperature range <em>T</em> <span> <span>( ll )</span> </span> <em>T</em><sub><em>c</em></sub>. The magnetic properties of the multilayer structure are numerically simulated using the anisotropic Heisenberg model. In the vicinity of <em>T</em><sub><em>c</em></sub>, easy-plane anisotropy is shown to exert a predominant influence on the magnetic properties of the structure as compared to the influence of single-ion anisotropy. In the low-temperature range, the switching of the magnetic state of the ferromagnetic film in an external field leads to the appearance of specific features in hysteresis effects due to the competition of two types of magnetic anisotropy. The magnetic structure exhibits a size-induced transition from the behavior caused by easy-plane anisotropy to the behavior caused by single-ion anisotropy. The revealed size-induced transition is accompanied by a spin-flop effect.</p> </span>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462256","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 : 2023-10-26DOI: 10.1134/S1063776123090030
A. V. Bakulin, A. S. Kulkov, S. E. Kulkova
The influence of substitutional impurities on adhesion at the TiAl/Al2O3 interface with an oxygen termination has been studied by the projector augmented-wave method within the density functional theory. It has been shown that transition metals and a number of s,p-elements substituting for the interfacial titanium atom reduce adhesion, whereas Group VB and VIB elements enhance chemical bonding at the interface. The local densities of states, charge density distribution, overlap populations for interfacial atom bonding, and other electronic characteristics have been calculated that make it possible to reveal key factors influencing adhesion at the alloy–oxide interface. A correlation has been found between the influence of impurities on bonding energy at the inner and outer interfaces. A comparison of obtained data with those for the interface with Ti-enriched Ti3Al alloy shows that the interface loses strength with decreasing Ti content in the alloy.
{"title":"Influence of Impurities on Adhesion at the TiAl/Al2O3 Interface","authors":"A. V. Bakulin, A. S. Kulkov, S. E. Kulkova","doi":"10.1134/S1063776123090030","DOIUrl":"10.1134/S1063776123090030","url":null,"abstract":"<p>The influence of substitutional impurities on adhesion at the TiAl/Al<sub>2</sub>O<sub>3</sub> interface with an oxygen termination has been studied by the projector augmented-wave method within the density functional theory. It has been shown that transition metals and a number of <i>s</i>,<i>p</i>-elements substituting for the interfacial titanium atom reduce adhesion, whereas Group VB and VIB elements enhance chemical bonding at the interface. The local densities of states, charge density distribution, overlap populations for interfacial atom bonding, and other electronic characteristics have been calculated that make it possible to reveal key factors influencing adhesion at the alloy–oxide interface. A correlation has been found between the influence of impurities on bonding energy at the inner and outer interfaces. A comparison of obtained data with those for the interface with Ti-enriched Ti<sub>3</sub>Al alloy shows that the interface loses strength with decreasing Ti content in the alloy.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910747","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 : 2023-10-26DOI: 10.1134/S106377612309008X
N. Yu. Agafonova, E. A. Dobrynina, N. A. Filimonova, I. R. Shakiryanova
Time series of gamma-ray photons from natural radioactivity measured with the Large Volume Detector (LVD) at the Gran Sasso underground laboratory (Laboratori Nazionali del Gran Sasso, Italy) have been analyzed. The instrument is used to detect neutrinos from gravitational collapses of stellar cores in the Galaxy. The background of the experiment is due to neutrons and gamma-ray photons from the decays of daughter nuclei of uranium and thorium. An analysis of periodic variations of the number of gamma-ray photons caused by the radon concentration in the underground laboratory has shown the presence of diurnal, weekly, monthly, and annual modulations. Data collected from 2004 to 2021, including a period of low activity in the hall of the Gran Sasso laboratory during the COVID-19 pandemic, have been reported.
{"title":"Periodic Variations of the Radon Concentration Measured by the Large Volume Detector at the Gran Sasso Underground Laboratory","authors":"N. Yu. Agafonova, E. A. Dobrynina, N. A. Filimonova, I. R. Shakiryanova","doi":"10.1134/S106377612309008X","DOIUrl":"10.1134/S106377612309008X","url":null,"abstract":"<p>Time series of gamma-ray photons from natural radioactivity measured with the Large Volume Detector (LVD) at the Gran Sasso underground laboratory (Laboratori Nazionali del Gran Sasso, Italy) have been analyzed. The instrument is used to detect neutrinos from gravitational collapses of stellar cores in the Galaxy. The background of the experiment is due to neutrons and gamma-ray photons from the decays of daughter nuclei of uranium and thorium. An analysis of periodic variations of the number of gamma-ray photons caused by the radon concentration in the underground laboratory has shown the presence of diurnal, weekly, monthly, and annual modulations. Data collected from 2004 to 2021, including a period of low activity in the hall of the Gran Sasso laboratory during the COVID-19 pandemic, have been reported.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910168","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 : 2023-10-26DOI: 10.1134/S1063776123090066
V. R. Skoy
To date, the violation of T invariance (TI) has been experimentally established for the decays [J. H. Christenson et al., Phys. Rev. Lett. 13, 138 (1964)] and oscillations [A. Angelopoulos et al., Phys. Lett. B 444, 43 (1998)] of neutral kaons. Phenomenologically, TI violation in the system of neutral kaons is associated with the difference of the Kobayashi–Maskawa phase from zero (or from π) in the standard model of the electroweak interaction. For nucleon–nucleus interactions, this phase turns out to be very small [P. Herszeg, in Symmetries and Fundamental Interactions in Nuclei, World Scientific, Singapore (1995), p. 89)]. Estimates of the nucleon–nucleon matrix element corresponding to TI violation in various models are given in [V. Gudkov, in Fundamental Physics with Pulsed Neutron Beams, World Scientific, Singapore (2001), p. 117]. All these estimates are small and have a large spread. Therefore, the verification of TI in nuclear processes actually means a search for other mechanisms for its violation. Below is a description of the experimental methods for TI verification in the total interaction cross sections of low-energy resonance neutrons with unpolarized nuclei with the use of the polarization–asymmetry (PA) theorem.
{"title":"Verification of T Invariance in the Total Interaction Cross Section of Neutrons with Unpolarized Nuclei Using the Polarization–Asymmetry Theorem","authors":"V. R. Skoy","doi":"10.1134/S1063776123090066","DOIUrl":"10.1134/S1063776123090066","url":null,"abstract":"<p>To date, the violation of T invariance (TI) has been experimentally established for the decays [J. H. Christenson et al., Phys. Rev. Lett. <b>13</b>, 138 (1964)] and oscillations [A. Angelopoulos et al., Phys. Lett. B <b>444</b>, 43 (1998)] of neutral kaons. Phenomenologically, TI violation in the system of neutral kaons is associated with the difference of the Kobayashi–Maskawa phase from zero (or from π) in the standard model of the electroweak interaction. For nucleon–nucleus interactions, this phase turns out to be very small [P. Herszeg, in <i>Symmetries and Fundamental Interactions in Nuclei</i>, World Scientific, Singapore (1995), p. 89)]. Estimates of the nucleon–nucleon matrix element corresponding to TI violation in various models are given in [V. Gudkov, in <i>Fundamental Physics with Pulsed Neutron Beams</i>, World Scientific, Singapore (2001), p. 117]. All these estimates are small and have a large spread. Therefore, the verification of TI in nuclear processes actually means a search for other mechanisms for its violation. Below is a description of the experimental methods for TI verification in the total interaction cross sections of low-energy resonance neutrons with unpolarized nuclei with the use of the polarization–asymmetry (PA) theorem.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910804","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 : 2023-10-26DOI: 10.1134/S1063776123090108
V. L. Kuzmin, A. Yu. Valkov, Yu. A. Zhavoronkov
The theory is developed and numerical simulation is performed for the coherent backscattering effect in a strongly inhomogeneous random medium with a finite spatial coherence length. It is shown using the Monte Carlo method that the limitation imposed on the number of scattering events corresponds to lowering of incident radiation coherence and leads to angular broadening of the backscattering peak, extending the possibility of using coherent backscattering in biomedical applications. Based on the diagrammatic technique, the modeling of coherent backscattering is developed for the first time beyond the frames of the ladder approximation.
{"title":"Coherent Backscattering Peak for Radiation with Low Spatial Coherence","authors":"V. L. Kuzmin, A. Yu. Valkov, Yu. A. Zhavoronkov","doi":"10.1134/S1063776123090108","DOIUrl":"10.1134/S1063776123090108","url":null,"abstract":"<p>The theory is developed and numerical simulation is performed for the coherent backscattering effect in a strongly inhomogeneous random medium with a finite spatial coherence length. It is shown using the Monte Carlo method that the limitation imposed on the number of scattering events corresponds to lowering of incident radiation coherence and leads to angular broadening of the backscattering peak, extending the possibility of using coherent backscattering in biomedical applications. Based on the diagrammatic technique, the modeling of coherent backscattering is developed for the first time beyond the frames of the ladder approximation.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910799","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 : 2023-10-26DOI: 10.1134/S1063776123090042
F. F. Goryaev
A theoretical method for evaluating the single-electron capture (SEC) cross sections in collisions of fast ions with a ground-state H2 molecule is presented. The scattering problem for ion-molecule collisions is formulated in the impact parameter representation using the relation between the quantum-mechanical amplitude and quasi-classical impact parameter one. The capture amplitudes and corresponding probabilities of capture to (nlm) states of an incident ion are derived within the framework of the Brinkman–Kramers approximation. The general expressions for the SEC probability amplitudes to n-states, summed over l and m quantum numbers, are deduced, from which the corresponding SEC probabilities can be then calculated using a procedure of multichannel normalization. The dependence of the differential cross sections, integrated over projectile impact parameters, on the molecular orientation for charge exchange in H+ + H2 collisions is considered and compared with measurements and other calculations. Total SEC cross sections, integrated over the molecular orientations and summed over n-states for several bare and dressed ions, are calculated and compared with available experimental data and results of calculations by means of other theoretical methods.
{"title":"Single Electron Capture in Collisions of Fast Ions with Molecular Hydrogen in the Impact Parameter Representation","authors":"F. F. Goryaev","doi":"10.1134/S1063776123090042","DOIUrl":"10.1134/S1063776123090042","url":null,"abstract":"<p>A theoretical method for evaluating the single-electron capture (SEC) cross sections in collisions of fast ions with a ground-state H<sub>2</sub> molecule is presented. The scattering problem for ion-molecule collisions is formulated in the impact parameter representation using the relation between the quantum-mechanical amplitude and quasi-classical impact parameter one. The capture amplitudes and corresponding probabilities of capture to (<i>nlm</i>) states of an incident ion are derived within the framework of the Brinkman–Kramers approximation. The general expressions for the SEC probability amplitudes to <i>n</i>-states, summed over <i>l</i> and <i>m</i> quantum numbers, are deduced, from which the corresponding SEC probabilities can be then calculated using a procedure of multichannel normalization. The dependence of the differential cross sections, integrated over projectile impact parameters, on the molecular orientation for charge exchange in H<sup>+</sup> + H<sub>2</sub> collisions is considered and compared with measurements and other calculations. Total SEC cross sections, integrated over the molecular orientations and summed over <i>n</i>-states for several bare and dressed ions, are calculated and compared with available experimental data and results of calculations by means of other theoretical methods.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910802","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 : 2023-10-26DOI: 10.1134/S1063776123090054
G. N. Klyushnikov, A. P. Serebrov
The problem of finding the depolarization losses of neutrons is investigated in connection with the need to determine the systematic error for experiments with magnetic storage of ultracold neutrons in traps. In this paper, we consider three methods to estimate the neutrons depolarization probability: classical, quantum mechanical and approximate one. They are used to estimate the depolarization probability of ultracold neutrons in two magnetic traps: the trap developed in Los Alamos National Laboratory (LANL) and the one designed in the neutron physics laboratory of “NRC Kurchatov Institute”—PNPI. It is shown that all three methods are successfully used to estimate depolarization. This is of particular importance to compare of theoretical predictions with the results of measurement in experiments to determine the neutron lifetime.
{"title":"On Estimation Methods of Depolarization Losses for Ultracold Neutrons in Magnetic Traps","authors":"G. N. Klyushnikov, A. P. Serebrov","doi":"10.1134/S1063776123090054","DOIUrl":"10.1134/S1063776123090054","url":null,"abstract":"<p>The problem of finding the depolarization losses of neutrons is investigated in connection with the need to determine the systematic error for experiments with magnetic storage of ultracold neutrons in traps. In this paper, we consider three methods to estimate the neutrons depolarization probability: classical, quantum mechanical and approximate one. They are used to estimate the depolarization probability of ultracold neutrons in two magnetic traps: the trap developed in Los Alamos National Laboratory (LANL) and the one designed in the neutron physics laboratory of “NRC Kurchatov Institute”—PNPI. It is shown that all three methods are successfully used to estimate depolarization. This is of particular importance to compare of theoretical predictions with the results of measurement in experiments to determine the neutron lifetime.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910803","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 : 2023-10-26DOI: 10.1134/S1063776123090145
A. V. Sobolev, V. I. Nitsenko, A. A. Belik, I. S. Glazkova, M. S. Kondratyeva, I. A. Presniakov
The electrical hyperfine interactions of the 57Fe probe nuclei stabilized in the structure of the BiMn7O12 manganite are studied by Mössbauer spectroscopy. Mössbauer spectra are measured in the para-electric temperature range, which includes the structural phase transitions I2/m ↔ Im(bar {3}) (T1 ≈ 600 K) and Im ↔ I2/m (T2 ≈ 450 K). The calculation of the parameters of the electric field gradient tensor with allowance for the dipole contributions of Bi3+ cations in the range of the first phase transition allowed us to confirm a random orientation of the dipole moments pBi in the cubic phase of the manganite (Im(bar {3})). Based on an analysis of the Mössbauer spectra recorded at T2 < T < T1, we considered various scenarios for the manifestation of the dynamic Jahn–Teller effect, which leads to the “melting” of the orbital order in the manganese sublattice, in terms of a two-level relaxation model.
{"title":"Jahn–Teller Ordering Dynamics in the Paraelectric BiMn7O12 Phase: 57Fe Probe Mössbauer Diagnostics","authors":"A. V. Sobolev, V. I. Nitsenko, A. A. Belik, I. S. Glazkova, M. S. Kondratyeva, I. A. Presniakov","doi":"10.1134/S1063776123090145","DOIUrl":"10.1134/S1063776123090145","url":null,"abstract":"<p>The electrical hyperfine interactions of the <sup>57</sup>Fe probe nuclei stabilized in the structure of the BiMn<sub>7</sub>O<sub>12</sub> manganite are studied by Mössbauer spectroscopy. Mössbauer spectra are measured in the para-electric temperature range, which includes the structural phase transitions <i>I</i>2/<i>m</i> ↔ <i>Im</i><span>(bar {3})</span> (<i>T</i><sub>1</sub> ≈ 600 K) and <i>Im</i> ↔ <i>I</i>2/<i>m</i> (<i>T</i><sub>2</sub> ≈ 450 K). The calculation of the parameters of the electric field gradient tensor with allowance for the dipole contributions of Bi<sup>3+</sup> cations in the range of the first phase transition allowed us to confirm a random orientation of the dipole moments <i>p</i><sub>Bi</sub> in the cubic phase of the manganite (<i>Im</i><span>(bar {3})</span>). Based on an analysis of the Mössbauer spectra recorded at <i>T</i><sub>2</sub> < <i>T</i> < <i>T</i><sub>1</sub>, we considered various scenarios for the manifestation of the dynamic Jahn–Teller effect, which leads to the “melting” of the orbital order in the manganese sublattice, in terms of a two-level relaxation model.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71910856","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}