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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mironov V. L., Kerr Y. H., Kosolapova L. G., Savin I. V., Muzalevskiy K. V.
Заглавие : A temperature-dependent dielectric model for thawed and frozen organic soil at 1.4 GHz
Коллективы : Russian Science Foundation [14-17-00656]
Место публикации : IEEE J. Sel. Top. Appl. Earth Observ. Remote Sens.: IEEE-Institute Electrical and Electronics Engineers, 2015. - Vol. 8, Is. 9. - P.4470-4477. - ISSN 1939-1404, DOI 10.1109/JSTARS.2015.2442295. - ISSN 2151-1535
Примечания : Cited References:19. - This work was supported in part by a grant from the Russian Science Foundation under Project 14-17-00656
Предметные рубрики: moisture retrieval algorithm
active layer
validation
Ключевые слова (''Своб.индексиров.''): dielectric constant--dielectric losses--dielectric measurement--l-band--modeling--soil moisture--soil properties
Аннотация: A single-frequency dielectric model for thawed and frozen Arctic organic-rich (80%-90% organic matter) soil was developed. The model is based on soil dielectric data that were measured over the ranges of volumetric moisture from 0.007 to 0.573 cm3/cm3, dry soil density from 0.564 to 0.666 g/cm3, and temperature from 25°C to -30°C (cooling run), at the frequency of 1.4 GHz. The refractive mixing model was applied to fit the measurements of the soil's complex refractive index (CRI) as a function of soil moisture, with the values of temperature being fixed. Using the results of this fitting, the parameters of the refractive mixing model were derived as a function of temperature. These parameters involve the CRIs of soil solids as well as bound, transient, and free soil water components. The error of the dielectric model was evaluated by correlating the predicted complex relative permittivity (CRP) values of the soil samples with the measured ones. The coefficient of determination (R2) and the root-mean-square error (RMSE) were estimated to be R2 = 0.999, RMSE = 0.27 and R2 = 0.993, RMSE = 0.18 for the real and imaginary parts of the CRP, respectively. These values are in the order of the dielectric measurement error itself. The proposed dielectric model can be applied in active and passive remote-sensing techniques used in the areas with organicrich soil covers, mainly for the SMOS, SMAP, and Aquarius missions.
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2.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Burmitskikh A. V., Boev N. M., Izotov A. V., Andyuseva V. G.
Заглавие : Automated measuring unit for analysis of thin magnetic film ferroresonance spectrum
Коллективы : International Siberian Conference on Control and Communications
Место публикации : International Siberian Conference on Control and Communications, SIBCON 2019: Proceedings: IEEE, 2019. - Ст.8729594. - , DOI 10.1109/SIBCON.2019.8729594
Примечания : Cited References: 6
Аннотация: This paper considers hardware and software for automated analysis of thin magnetic film ferroresonance spectrum to determine the rate of growth and decrease in ferroresonance spectrum (conversion factor parameter). The measuring element of automated system is the strip line which is short-circuited. The measuring unit is used to study Ni 80 Fe 20 permalloy films, with thickness of more than 300 Å. Conversion factor, magnetic permeability μ, uniaxial magnetic anisotropy, ferromagnetic spectrum resonance line width, saturation magnetization are analyzed from 50 MHz to 2 GHz frequency range. The magnetic films are used to design frequency selective filters, phase shifters and weak-field magnetic sensors. The thin magnetic film sensors are high sensitive magnetometers, with wide frequency range, low dimensions and weight [1]. © 2019 IEEE.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Local-Field Anisotropy of a Light Wave in Quasi-Two-Dimensional Soft-Matter Objects
Коллективы :
Разночтения заглавия :авие SCOPUS: Local-field anisotropy of a light wave in quasi-two-dimensional soft-matter objects
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2010. - Vol. 110, Is. 4. - P622-636. - ISSN 1063-7761, DOI 10.1134/S1063776110040102
Примечания : Cited References: 73. - This study was supported by the Presidium of the Russian Academy of Sciences within the Program of Basic Research (project no. 27.1) and the Siberian Branch of the Russian Academy of Sciences within the Program of Interdisciplinary Basic Research (project no. 5).
Предметные рубрики: INTEGRATED OPTICAL TECHNIQUES
LANGMUIR-BLODGETT-FILMS
SMECTIC LIQUID-CRYSTALS
UNIAXIAL POLYMER-FILMS
MOLECULAR-ORIENTATION
INTERNAL FIELD
DIELECTRIC-CONSTANT
SPECTRAL FEATURES
REFRACTIVE-INDEX
THIN-FILMS
Ключевые слова (''Своб.индексиров.''): anisotropic films--bilayer lipid membrane--chemical structure--comblike polymers--conductive polymer--discotics--dispersion of refractive index--experimental data--experimental values--hexatic-b phase--isotropization--langmuir films--light wave--lorentz--macromolecular polymers--model approach--molecular polarizabilities--optical axis--order parameter--orientational order parameters--orientational orderings--orientational orders--smectic layers--smectic-a--smectics--soft matter--structural unit--sub-micron films--substrate types--tensor components--visible range--anisotropy--cell membranes--conductive plastics--conjugated polymers--electronic structure--light measurement--liquid crystal polymers--molecules--multilayer films--organic polymers--phase transitions--polarization--polymers--refractive index--substrates--tensors--two dimensional--conductive films
Аннотация: Experimental values of the Lorentz tensor components L-j for uniaxial quasi-two dimensional "soft matter" objects on substrates (bilayer lipid membranes, multilayer Langmuir films, smectics A, hexatic smectics B, submicron films of discotics Col(hd), micron anisotropic films of liquid-crystal comblike polymers and macromolecular polymers, submicron films of conjugated conductive polymers), freely suspended sub-micron films of smectics A, and uniaxially stretched micron films of conjugated conductive polymers have been determined using dispersion of refractive indices in the visible range. The dependences of the components L-j on the type of orientation (axial, planar) of uniaxial molecules (structural units of the film) with respect to the optical axis of the film, the film thickness, the substrate type, the chemical structure of molecules, and their long-range orientational order are established. It is revealed that the smectic A-hexatic B phase transition and two-dimensional crystallization of the smectic layer lead to changes in the components L-j due to the change in the orientational ordering of molecules as a result of the relation between the orientational and hexatic order parameters. All the above objects are characterized by isotropization of the Lorentz tensor L and the local-field tensor f with a simultaneous decrease in the birefringence of the sample and in the anisotropy of the molecular polarizability due to the change in the electronic structure of molecules. The correction for the anisotropy of the local-field tensor f to the orientational order parameter or the anisotropy of the molecular polarizability increases. The existing model approaches to calculating the components L-j for the objects under consideration are compared with the experimental data.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bikbaev R. G., Vetrov S. Ya., Timofeev I. V.
Заглавие : Transparent conductive oxides for the epsilon-near-zero Tamm plasmon polaritons
Место публикации : J. Opt. Soc. Am. B. - 2019. - Vol. 36, Is. 10. - P.2817-2823. - ISSN 07403224 (ISSN), DOI 10.1364/JOSAB.36.002817
Примечания : Cited References: 44. - The reported study was funded by RFBR according to the research project No 18-32-00053 and financial support RFBR and MOST according to the research project No 19-52-52006.
Аннотация: We demonstrate the possibility of using transparent conducting oxides [aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium tin oxide (ITO)] to form Tamm plasmon polaritons in the near-infrared spectral range where the permittivity of oxides is near zero. The spectral properties of the structures are investigated in the framework of the temporal coupled-mode theory and confirmed by the transfer matrix method. It is found that in the critical coupling conditions, the maximal Q-factor of a Tamm plasmon polariton is achieved when a photonic crystal is conjugated with the AZO film, while at the conjugation with the ITO films, the broadest spectral line is obtained. The sensitivity of the wavelength and spectral width of the Tamm plasmon polariton to changes in the oxide film thickness, bulk concentration of a dopant, and angle of incidence is demonstrated.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bobrov P. P., Kroshka E. S., Muzalevskiy K. V.
Заглавие : The effect of dielectric relaxation processes on the complex dielectric permittivity of soils at frequencies from 10 kHz to 8 GHz—Part II: Broadband analysis
Колич.характеристики :11 с
Место публикации : IEEE Trans. Geosci. Remote Sens. - 2024. - Vol. 62. - Ст.2000411. - ISSN 01962892 (ISSN), DOI 10.1109/TGRS.2023.3340693. - ISSN 15580644 (eISSN)
Примечания : Cited References: 51
Аннотация: This article is the second in a series evaluating the effect of dielectric relaxation processes on the relatively effective complex dielectric permittivity (RCP) of soils. Part II is based on the results of experimental measurements in the frequency range 10 kHz to 8–20 GHz. The broadband dielectric spectrum model includes the high-frequency part as a model of the dielectric mixture and the relaxation part as the sum of three relaxation processes modeled by the Debye and Cole–Cole formulas. For modeling the high-frequency part of the spectrum, the Dobson and Mironov models were considered as possible options. As stated in Part I, the influence of relaxation processes on the imaginary part of the RCP extends up to frequencies of units of gigahertz. The increase in the imaginary part in these models was compensated by unrealistically high values of the specific electrical conductivity of free and bound water. We examined the correspondence of these models to experimental data at frequencies above 2–5 GHz, assuming that the conductivity of bound and free water is zero. The parameters of relaxation processes were found while solving the least-square optimization problem using the technique for determining the continuous distribution of relaxation times (DRTs). Found process parameters depend on the content of clay, organic carbon, and moisture of the samples. The more clay is in the soil, the greater the strength of these processes is. The influence of organic carbon with the conditions being equal consists in the reduction of the real and imaginary parts of RCP.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bulgakov E. N., Pilipchuk A. S., Sadreev A. F.
Заглавие : Desktop laboratory of bound states in the continuum in metallic waveguide with dielectric cavities
Место публикации : Phys. Rev. B. - 2022. - Vol. 106, Is. 7. - Ст.075304. - ISSN 24699950 (ISSN), DOI 10.1103/PhysRevB.106.075304
Примечания : Cited References: 64. - We are grateful to Lujun Huang, Andrey Miroshnichenko and Yi Xu for presentation of unpublished paper and discussions. The research was supported by Russian Science Foundation No. 22-12-00070
Аннотация: We consider dielectric cavities whose radiation space is restricted by two parallel metallic planes. The TM solutions of the Maxwell equations of the system are equivalent to the solutions of periodical arrays of dielectric cavities. The system readily allows to achieve bound states in the continuum (BICs) of any type including topological BICs as dependent on position and orientation of the cavities relative to the planes and that extremely facilitates experimental studies in comparison to infinite arrays of the cavities. We show the effect of merging of topologically protected BICs that pushes the square asymptotic of the Q factor into the power degree 4 or even 6.
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7.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Bulgakov E. N., Pichugin K. N., Sadreev A. F.
Заглавие : Interaction between dielectric particles enhances the Q factor.
Коллективы : International Conference on Metamaterials and Nanophotonics
Место публикации : International Conference on Metamaterials and Nanophotonics (4 ; 2019 ; 15 - 19 July ; St. Petersburg, Russian Federation). Journal of Physics: Conference Series. - 2020. - Vol. 1461, Is. 1. - Ст.012144. - , DOI 10.1088/1742-6596/1461/1/012144
Примечания : Cited References: 22. - This work was supported by Russian Science Foundation through Grant 19-02-00055. A. S. thanks A. Bogdanov for numerous and fruitful discussions
Аннотация: We consider resonant modes of two dielectric identical particles which can be classified as symmetric and anti symmetric combinations of the resonant modes of individual particles. We show that an approaching of two particles gives rise to an avoided crossing of resonant poles because of interaction between the disks. That in turn results in strong enhancement of the quality factor factor of two disks compared to isolated disks.
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8.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Burmitskikh A. V., Boev N. M., Kleshnina S. A.
Заглавие : Measurement of thin film magnetic characteristics in the radio frequency range
Коллективы : International Siberian Conference on Control and Communications
Место публикации : SIBCON 2021 - International Siberian Conference on Control and Communications: IEEE, 2021. - Ст.9438908. - , DOI 10.1109/SIBCON50419.2021.9438908
Примечания : Cited References: 21. - The reported study was funded by RFBR, project number 19-32-90066\19
Аннотация: The paper presents a method for measuring the ferromagnetic resonance spectrum in the radio frequency range (4 MHz). A high-frequency generator operating in the autodyne mode was used to measure the magnetic characteristics of thin ferromagnetic films. Theoretical equations for ferromagnetic resonance excitations have been presented. Experimental results for the samples of nanocrystalline thin permalloy magnetic films with low magnetostriction and different values of the anisotropy field were obtained. Ferromagnetic resonance in the radio frequency range proved to be an excellent mean for measuring the value and direction of the magnetic anisotropy field in thin magnetic films.
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9.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Chistyakov N. S., Tuschkov B. P.
Заглавие : Constituents measurement of complex superhighfrequency susceptibility of magnetic films
Коллективы : Академия наук СССР, Научный совет по комплексной проблеме "Физика твердого тела" АН СССР, Институт физики им. Л.В. Киренского Сибирского отделения РАН, Иркутский государственный педагогический институт, International colloquium on physics of magnetic films, Международный коллоквиум по физике магнитных пленок
Место публикации : International colloquium on physics of magnetic films: [program and abstracts]/ chairman L. V. Kirensky ; vice-chaiman: V. A. Buravikhin, R. V. Telesnin ; progr. and publ. com. N. M. Salansky ; progr. com.: V. A. Ignatchenko, Yu. V. Zakharov [et al]. - Irkutsk, 1968. - Section Ferromagnetic resonance, spin-wave resonance, high-frequency properties. - Ст.6-A.1. - P.59 (Шифр В37/H99-248389966)
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mamalis A. G., Ovchinnikov S. G., Petrov M. I., Balaev D. A., Shaihutdinov K. A., Gohfeld D. M., Kharlamova S. A., Vottea I. N.
Заглавие : Composite materials on high-T-c superconductors and BaPbO3, Ag basis
Коллективы : International Conference on New Theories, Discoveries and Applications of Superconductors and Related Materials
Разночтения заглавия :авие SCOPUS: Composite materials on high-Tc superconductors and BaPbO3, Ag basis
Место публикации : Physica C. - 2001. - Vol. 364. - P.174-177. - ISSN 0921-4534, DOI 10.1016/S0921-4534(01)00749-3
Примечания : Cited References: 9
Ключевые слова (''Своб.индексиров.''): composite high-t-c superconductors--superconducting fault current limiter--composite high-tc superconductors--superconducting fault current limiter--composite materials--electric fault currents--interfaces (materials)--magnetic variables measurement--mathematical models--scanning electron microscopy--spectrometry--superconducting transition temperature--superconductivity--x ray diffraction analysis--solid state reactions--high temperature superconductors
Аннотация: The preparation., processing and characterization of the composite materials on high-T-c superconductor (HTSC) basis, YBa2Cu3O7/Ag and Y0.75Lu0.25Ba2Cu3O7/BaPbO3, is reported. The initial components YBa2Cu3O7 and BaPbO3 were prepared by the standard solid state reaction technique. The microstructures of the samples were observed by scanning electron microscopy. whilst the XRD paterns of the composites HTSC+Ag and HTSC+BaPbO3 revealed the 123 superconducting phase and the Ag or BaPbO3 structure. The chemical compositions of the powders and the interface zone were found by employing energy dispersive spectrometry. The resistive and magnetic measurements of the composites indicated the transition temperature 93.5 K. Application of such composite materials in the construction of a superconducting fault current limiter model is reported. (C) 2001 Elsevier Science B.V. All rights reserved.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Ryabinkina L. I., Abramova G. M., Romanova O. B., Vorotynov A. M., Velikanov D. A., Kiselev N. I., Balaev A. D.
Заглавие : Conductivity, weak ferromagnetism, and charge instability in an alpha-MnS single crystal
Разночтения заглавия :авие SCOPUS: Conductivity, weak ferromagnetism, and charge instability in an α-MnS single crystal; авие SCOPUS: Conductivity, weak ferromagnetism, and charge instability in an ?-MnS single crystal
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2005. - Vol. 71, Is. 12. - Ст.125204. - ISSN 1098-0121, DOI 10.1103/PhysRevB.71.125204; Phys. Rev. B Condens. Matter Mater. Phys. - 2005. - Vol. 71, Is. 12. - Ст.125204. - Вариант Sopus
Примечания : Cited References: 11
Предметные рубрики: MANGANITES
Ключевые слова (''Своб.индексиров.''): ferromagnetic material--manganese derivative--absorption spectroscopy--article--calculation--conductance--crystal--electron spin resonance--hybridization--magnetic field--magnetism--measurement--molecular interaction--temperature dependence--temperature measurement--ferromagnetic material--manganese derivative--absorption spectroscopy--article--calculation--conductance--crystal--electron spin resonance--hybridization--magnetic field--magnetism--measurement--molecular interaction--temperature dependence--temperature measurement
Аннотация: The temperature dependence of resistivity, magnetization, and electron-spin resonance of the α-MnS single crystal were measured in temperature range of 5 K T 550 K. Magnetization hysteresis in an applied magnetic field up to 0.7 T at T
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sadreev A. F., Bulgakov E. N., Pilipchuk A. S., Miroshnichenko A., Huang L.
Заглавие : Degenerate bound states in the continuum in square and triangular open acoustic resonators
Место публикации : Phys. Rev. B. - 2022. - Vol. 106, Is. 8. - Ст.085404. - ISSN 24699950 (ISSN), DOI 10.1103/PhysRevB.106.085404
Примечания : Cited References: 43
Аннотация: We consider square and equilateral triangular open acoustic resonators with the C4v and C3v symmetries, respectively. There is a unique property of square and triangular resonators of accidental number fourfold degeneracy of eigenstates that gives rise to twofold-degenerate Friedrich-Wintgen (FW) bound states in the continuum (BICs). Compared to usual FW BICs, the degenerate FW BICs maintain high Q factor in wide range of the size of resonators. That removes the fabrication difficulties of the proper choice of resonator. The presence of degenerate BICs in triangular resonators is extremely sensitive to switch output flows by small perturbations with 100% efficiency.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aleksandrovsky A. S., Vyunishev A. M., Zaitsev A. I., Pospelov G. I., Slabko V. V.
Заглавие : Diagnostics of fs pulses by noncollinear random quasi-phase-matched frequency doubling
Место публикации : Appl. Phys. Lett. - 2011. - Vol. 99, Is. 21. - Ст.211105. - ISSN 0003-6951, DOI 10.1063/1.3664094
Примечания : Cited References: 12. - The work was supported by Ministry of Education and Science of Russian Federation (Contract No. 16.740.11.0150); Grant of President of Russian Federation for support of leading scientific schools Grant Nos. SS-4645.2010.2 and RNP.2.1.1.3455 and Projects Nos. 2.5.2 and 3.9.1 of PSB RAS and 27.1 and 5 of SB RAS. A. M. Vyunishev is grateful for the support from Krasnoyarsk Regional Fund of Science and Technical Activity Support.
Ключевые слова (''Своб.индексиров.''): autocorrelation measurement--cross-correlation measurements--fs pulse--noncollinear--nonlinear photonic crystals--nonuniformity--quasi-phase-matched frequency doubling--random structures--tetraborate--vacuum ultraviolets--wide spectral range--band structure--frequency doublers--strontium--photonic crystals
Аннотация: Noncollinear random quasi-phase-matched frequency doubling in nonlinear photonic crystal (NPC) of strontium tetraborate (SBO) can be used for background-free autocorrelation measurements of ultrashort pulses in wide spectral range without any angular tuning of nonlinear photonic crystal. Nonuniformity of reciprocal superlattice vectors spectrum of random structure does not affect the accuracy of measurement. Nonlinear photonic crystals of strontium tetraborate are attractive medium for cross-correlation measurements in deep and vacuum ultraviolet. VC 2011 American Institute of Physics. [doi:10.1063/1.3664094]
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gao H., Molokeev M. S., Chen Q., Yang X., Wang X., Ma B.
Заглавие : Effect of ligand environment of rare-earth ions on temperature measurement performance of SrAO4:xEu3+ (A = Mo and W) phosphors
Место публикации : Ceram. Int. - 2022. - Vol. 48, Is. 24. - P.36835-36844. - ISSN 02728842 (ISSN), DOI 10.1016/j.ceramint.2022.08.247
Примечания : Cited References: 58. - This work was supported by the National Natural Science Foundation of China (Grant No. 51802172) and the Natural Science Foundation of Qinghai Province (Grant No. 2021-ZJ-713)
Аннотация: Molybdate and tungstate with scheelite-type structure are excellent self-luminescent materials, which can be used as ideal hosts for the doping of rare-earth ions. In this study, a series of Eu3+-activated SrAO4 (A = Mo and W) phosphors were successfully synthesized, and their crystal structures, photoluminescence properties, and temperature measurement performance were analyzed in detail. These phosphors were excited by UV light (291 nm and 247 nm, respectively), with clear energy transfer (ET) (MoO42−→Eu3+ or WO42−→Eu3+). According to fluorescence intensity ratio (FIR) and Judd–Ofelt (J–O) theory, compared to SrWO4:0.01Eu3+ phosphor, SrMoO4:0.01Eu3+ phosphor exhibited better thermal stability, with relatively low Sa value (maximum values were 5.082 %K−1 and 20.74 %K−1, respectively), and their Sr values were not significantly different (maximum values were 0.864 %K−1 and 0.83 %K−1, respectively). Sa value was negatively correlated to central asymmetry of Eu3+, but the optimal Sr value tended to be more suitable for central asymmetry of Eu3+. In addition, Eu3+ exhibited stronger central asymmetry as well as covalency of Eu–O bond in SrMoO4. Results reveal that SrMoO4:xEu3+ and SrWO4:xEu3+ can be used for luminescent thermometers.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Korshunov M. M., Shneyder E. I.
Заглавие : Effect of short antiferromagnetic correlations on the normal and superconducting properties in copper oxides
Место публикации : Diffusion and Defect Data Pt.B: Solid State Phenomena: Trans Tech Publications Ltd, 2011. - Vol. 168-169. - С. 561-566. - ISSN 10120394 (ISSN); 9783037850213 (ISBN), DOI 10.4028/www.scientific.net/SSP.168-169.561
Ключевые слова (''Своб.индексиров.''): high temperature superconductivity--short range antiferromagnetic order--strong electron correlations--antiferromagnetic materials--antiferromagnetism--copper oxides--electron correlations--electron density measurement--antiferromagnetism--electron correlations--ab initio--antiferromagnetic correlations--cuprates--high-t--high-temperature superconductivity--hubbard--low energies--multiband model--short range antiferromagnetic order--strong electron correlations--superconducting properties--t-j models--antiferromagnetic orderings--superconductivity--copper oxides--high temperature superconductivity
Аннотация: The abnormal "normal" state and origin of high temperature superconductivity in cuprates are still not clear [1-2]. The strong electron correlations (SEC) are known to be one of the main difficulties for the theory of high- Tc cuprates. The conventional LDA (local density approximation) approach to the band structure fails in the regime of SEC. Various realistic multiband models of a CuO2 layer at low energy result in the effective Hubbard or t - J models [3-7]. The hybrid LDA+GTB scheme [8] generates the low-energy effective t - t? - t? - J* model with all parameters calculated ab initio.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrichkov V. A., Ovchinnikov S. G., Nekrasov I. A., Pchelkina Z. V.
Заглавие : Electronic Structure of p-Type La1-xMx2+MnO3 Manganites in the Ferromagnetic and Paramagnetic Phases in the LDA plus GTB Approach
Разночтения заглавия :авие SCOPUS: Electronic structure of p-Type La 1-x M x 2+ MnO 3 manganites in the ferromagnetic and paramagnetic phases in the LDA + GTB approach
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 112, Is. 5. - P860-876. - ISSN 1063-7761, DOI 10.1134/S1063776111030101
Примечания : Cited References: 47. - This study was supported financially by integration project no. 40 of the Ural and Siberian Branches of the Russian Academy of Sciences, the program "Strong Electron Correlations" of the Russian Academy of Sciences, and the Russian Foundation for Basic Research (project no. 10-02-00251-a).
Предметные рубрики: DOUBLE-EXCHANGE
COLOSSAL MAGNETORESISTANCE
THIN-FILMS
PHYSICS
LA1-XSRXMNO3
RESISTIVITY
SEPARATION
TRANSPORT
MODEL
Ключевые слова (''Своб.индексиров.''): complex structure--cubic materials--ferromagnetic phase--half metals--jahn teller effect--metal properties--metal types--orbitals--p-type--paramagnetic phase--paramagnetic phasis--quasi particles--spectral intensity--spin projections--strong electron correlations--barium--density functional theory--electron correlations--electron density measurement--electronic properties--electronic structure--fermi level--ferromagnetic materials--ferromagnetism--manganese oxide--manganites--paramagnetic materials--paramagnetism--valence bands--lanthanum
Аннотация: The band structure, spectral intensity, and position of the Fermi level in doped p-type La1-xMx2+ MnO3 manganites (M = Sr, Ca, Ba) is analyzed using the LDA + GBT method for calculating the electronic structure of systems with strong electron correlations, taking into account antiferro-orbital ordering and using the Kugel-Khomskii ideas and real spin S = 2. The results of the ferromagnetic phase reproduce the state of a spin half-metal with 100% spin polarization at T = 0, when the spectrum is of the metal type for a quasiparticle with one spin projection and of the dielectric type for the other. It is found that the valence band becomes approximately three times narrower upon a transition to the paramagnetic phase. For the paramagnetic phase, metal properties are observed because the Fermi level is located in the valence band for any nonzero x. The dielectrization effect at the Curie temperature is possible and must be accompanied by filling of d(x) orbitals upon doping. The effect itself is associated with strong electron correlations, and a complex structure of the top of the valence band is due to the Jahn-Teller effect in cubic materials. DOI: 10.1134/S1063776111030101
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Orlov Y. S., Nekrasov I. A., Pchelkina Z. V.
Заглавие : Electronic structure, magnetic properties, and mechanism of the insulator-metal transition in LaCoO3 taking into account strong electron correlations
Разночтения заглавия :авие SCOPUS: Electronic structure, magnetic properties, and mechanism of the insulator-metal transition in LaCoO 3 taking into account strong electron correlations
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 112, Is. 1. - P140-151. - ISSN 1063-7761, DOI 10.1134/S1063776110061159
Примечания : Cited References: 36. - This study was supported financially by the Siberian and Ural Branches of the Russian Academy of Sciences (Integration Project no. 40), Department of Physics of the Russian Academy of Sciences (Program 2.3), Russian Foundation for Basic Research (Project nos. 09-02-00171-a and 10-02-00251), and Noncommercial "Dynasty" Foundation.
Предметные рубрики: SPIN-STATE TRANSITION
CHARGE
Ключевые слова (''Своб.индексиров.''): energy spectra--excited energy level--finite temperatures--gap state--gap widths--high temperature--high-temperature anomalies--insulator metal transition--pauli contribution--spin crossovers--strong electron correlations--temperature dependence--total magnetization--cobalt compounds--density functional theory--electron correlations--electron density measurement--electronic properties--electronic structure--magnetic susceptibility--semiconductor insulator boundaries--spectroscopy--metal insulator transition
Аннотация: The electronic structure of LaCoO3 at finite temperatures is calculated using the LDA+GTB method taking into account strong electron correlations and possible spin crossover upon an increase in temperature. Gap states revealed in the energy spectrum of LaCoO3 reduce the dielectric gap width upon heating; this allowed us to describe the insulator-metal transition observed in this compound at T = 500-600 K. The temperature dependence of the magnetic susceptibility with a peak at T a parts per thousand 100 K is explained by the Curie contribution from thermally excited energy levels of the Co3+ ion. At high temperatures, the Pauli contribution from a band electron is added and the total magnetization of LaCoO3 is considered as the sum M (tot) = M (loc) + M (band). The second term describes the band contribution appearing as a result of the insulator-metal transition and facilitating the emergence of a high-temperature anomaly in the magnetic susceptibility of LaCoO3.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Erkaev N. V., Semenov V. S., Biernat H. K.
Заглавие : Magnetic double-gradient instability and flapping waves in a current sheet
Место публикации : Phys. Rev. Lett.: AMER PHYSICAL SOC, 2007. - Vol. 99, Is. 23. - Ст.235003. - ISSN 0031-9007, DOI 10.1103/PhysRevLett.99.235003
Примечания : Cited References: 10
Предметные рубрики: MAGNETOTAIL CURRENT SHEET
CLUSTER
Ключевые слова (''Своб.индексиров.''): magnetic fields--magnetic properties--magnetohydrodynamics--velocity measurement--current sheets--flapping waves--magnetic gradients--stable regions--electromagnetic waves
Аннотация: A new kind of magnetohydrodynamic instability and waves are analyzed for a current sheet in the presence of a small normal magnetic field component varying along the sheet. These waves and instability are related to the existence of two gradients of the tangential (B(tau)) and normal (B(n)) magnetic field components along the normal (del(n)B(tau)) and tangential (del(tau)B(n)) directions with respect to the current sheet. The current sheet can be stable or unstable if the multiplication of two magnetic gradients is positive or negative. In the stable region, the kinklike wave mode is interpreted as so-called flapping waves observed in Earth's magnetotail current sheet. The kink wave group velocity estimated for the Earth's current sheet is of the order of a few tens of kilometers per second. This is in good agreement with the observations of the flapping motions of the magnetotail current sheet.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Denisova E. A., Iskhakov R. S., Stolyar S. V., Komogortsev S. V., Chekanova L. A., Maltsev V. K., Kalinin Y. E., Sitnikov A. V.
Заглавие : Exchange interaction in the Co-SiO2 nanocomposite films
Место публикации : TRENDS IN MAGNETISM. - 2011. - Vol. 168-169. - С. 265-268. - ISSN 10120394 (ISSN); 9783037850213 (ISBN), DOI 10.4028/www.scientific.net/SSP.168-169.265
Ключевые слова (''Своб.индексиров.''): exchange coupling parameter--ferromagnetic resonance--granular composite films--cobalt--exchange coupling--exchange interactions--ferromagnetic materials--ferromagnetic resonance--ferromagnetism--magnetic resonance measurement--nanocomposite films--nanocomposites--nuclear magnetic resonance--resonance--silicon compounds--spin waves--cobalt--exchange coupling--exchange interactions--ferromagnetic materials--ferromagnetic resonance--ferromagnetism--magnetic resonance measurement--magnetism--nanocomposite films--nuclear magnetic resonance--spin fluctuations--spin waves--co content--coupling parameters--dispersion relations--granular composite films--magnetic measurements--nanogranulars--nmr studies--structural state--granular composites--nano-granular--standing spin waves--composite films--composite films
Аннотация: The properties of Co-SiO2 nanogranular composite films, containing a Co volume fraction ranging from 0.3 to 0.8, have been characterized by means of magnetic measurements, NMR study, and ferromagnetic resonance. Thermal decrease of CoX(SiO2)100-X magnetization follows the T3/2 law and allows to estimate the exchange interaction constant A. With growing nominal Co content the transitions from granular to continuous structural state at 36% Co are registered by FMR measurements. The spectrum of standing spin-wave has been detected in the perpendicular experiment configuration for films with the Co content above 52 vol. %. It is found that the type of the dispersion relation of spin waves in Co-SiO2 composite films is affected by the exchange coupling fluctuations.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mironov V. L., Kosolapova L. G., Fomin S. V., Savin I. V.
Заглавие : Experimental analysis and empirical model of the complex permittivity of five organic soils at 1.4 GHz in the temperature range from −30 °C to 25 °C
Место публикации : IEEE Trans. Geosci. Remote Sensing. - 2019. - Vol. 51, Is. 6. - P.3778 - 3787. - ISSN 0196-2892, DOI 10.1109/TGRS.2018.2887117
Примечания : Cited References: 26. - This work was supported by the Russian Foundation for Basic Research under Grant 16-05-00572.
Аннотация: The dielectric measurements were made for five organic soils taken from the tundra territories of Alaska, Yamal, and Taimyr, with the content of organic matter varying from 35% to 80%. The measurements were carried out in the temperature range from −30 °C to 25 °C, frequencies from 0.45 to 16 GHz and soil moisture from close to zero to the field moisture capacity. The refractive mixing model was applied to fit the measurements of the soil’s complex refractive index (CRI) as a function of soil moisture, with the values of temperature being fixed. As a result, a respective dielectric model was developed. The amounts of bound and transient water in the thawed and frozen soils were introduced as parameters of the developed model and derived as a function of temperature and content of soil organic matter. The other parameters which concern the CRIs of soil solids as well as bound, transient, and liquid soil water or ice components were derived as a function of temperature. The errors of the proposed model estimated in terms of the values of normalized root-mean-sqaure error for the real and imaginary parts of the soil complex relative permittivity appeared to be 6%–7% and 23%, respectively. The proposed dielectric model can be applied in active and passive remote sensing, in particular, for the SMOS, SMAP, and Aquarius missions after testing in ground-based experiments.
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