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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vtyurin A. N., Krylov A. S., Goryainov S. V., Krylova S. N., Oreshonkov A. S., Voronov V. N.
Заглавие : A raman study of hydrostatic pressure induced phase transitions in Rb2KInF6 crystals
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2012. - Vol. 54, Is. 5. - P.934-936. - ISSN 1063-7834, DOI 10.1134/S1063783412050472
Примечания : Cited References: 16. - This study was supported by the Russian Foundation for Basic Research (project nos. 11-02-98002-r_sibir' and 09-02-00062), the Siberian Branch of the Russian Academy of Sciences (integration project no. 101), and the Council on Grants from the President of the Russian Federation (grant no. HSh-4645.2010.2).
Предметные рубрики: LATTICE-DYNAMICS
ELPASOLITES
SPECTRA
Аннотация: The Raman spectra of the elpasolite (Rb2KInF6) crystal have been studied in the pressure range from 0 to 5.3 GPa at a temperature of 295 K. A phase transition at a pressure of approximately 0.9 GPa has been found. An analysis of the variations in the spectral parameters has led to the conclusion that the phase transition to a distorted phase is accompanied by the doubling of the volume of the primitive cell of the initial cubic phase. Numerical calculations of the lattice dynamics in the Rb2KInF6 crystal have been performed. The numerical simulation has established that the phase transition at a pressure of 0.9 GPa is associated with condensation of the F (lg) mode. A probable high-pressure phase is the phase with space group C2/m.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrakovskaya E. A., Bulina N. V., Churilov G. N., Puzyr' A. P.
Заглавие : A study of the synthesis products of fullerenes with nickel and cobalt
Место публикации : Tech. Phys.: AMER INST PHYSICS, 2001. - Vol. 46, Is. 1. - P42-46. - ISSN 1063-7842, DOI 10.1134/1.1340883
Примечания : Cited References: 15
Предметные рубрики: COMPLEXES
SPECTRA
Аннотация: Qualitative analysis of the products of plasmochemical synthesis of fullerenes with metallic nickel and cobalt has been carried out using electron paramagnetic resonance (EPR) and electron microscopy. These studies show that the synthesis products are mainly fullerenes, metallic nanoparticles coated with an insulating layer, and isolated atomic clusters. (C) 2001 MAIK "Nauka/Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivanova N. B., Kazak N. V., Markov V. V., Ovchinnikov S. G., Rudenko V. V., Abd-Elmeguid M. M.
Заглавие : Analysis of the electrical and optical properties of VBO3 single crystals and Fe1-xVxBO3 solid solutions on the basis of a many-electron model of energy band structure
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2004. - Vol. 46, Is. 8. - P1462-1468. - ISSN 1063-7834, DOI 10.1134/1.1788779
Примечания : Cited References: 32. - One of the authors (M.M.A.) would like to thank the Deutsche Forschungsgemeinschaft (SFB608) for financial support. This study was supported by the Russian Foundation for Basic Research (project no. 03-02-16286), the program "Integration" (project no. B0017), and the program of the Division of Physical Sciences of the Russian Academy of Sciences "Strongly Correlated Electrons"
Предметные рубрики: MAGNETIC-PROPERTIES
CALCITE STRUCTURE
PHASE-TRANSITION
FERRIC BORATE
HIGH-PRESSURE
FEBO3
FE1-XCRXBO3
FERROMAGNET
MOSSBAUER
SPECTRA
Аннотация: A many-electron model of the energy band structure of VBO3 and of Fe1 - xVxBO3 solid solutions is proposed with strong electron correlations taken into account. Experimental optical absorption spectra and data on the resistivity are discussed in the framework of the suggested model. Variation in the magnetic and electronic properties of VBO3 and Fe1 - xVxBO3 under high pressure is predicted. For VBO3, a Mott-Hubbard (insulator-metal) transition is expected in the high-pressure phase. In Fe1 - xVxBO3 solid solutions, a nontrivial variation in the properties is predicted, leading to the appearance of a different magnetic state. (C) 2004 MAIK "Nauka / Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Platunov M. S., Varnakov S. N., Zharkov S. M., Bondarenko G. V., Weschke E., Schierle E., Ovchinnikov S. G.
Заглавие : Analysis of the structure and magnetic properties of an interface in multilayered (Fe/Si) N nanostructures with the surface-sensitive XMCD method
Коллективы : Russian Foundation for Basic Research [13-02-01265a, 14-02-31051mol-a]; Council of the President of the Russian Federation for Support of Young Scientists and Leading Scientific Schools [NSh- 2886.2014.2]; Presidium of the Russian Academy of Sciences [24.34]; Ministry of Education and Science of the Russian Federation [02.G25.31.0043]
Место публикации : JETP Letters. - 2014. - Vol. 99, Is. 12. - P.706-711. - ISSN 0021-3640, DOI 10.1134/S002136401412011X. - ISSN 1090-6487
Примечания : Cited References: 26. - We are grateful to S.V. Komogortsev for stimulating discussions and to the management of BESSY II, Helmholtz-Zentrum Berlin, for the opportunity of performing experiments at the UE46-PGM1 beamline. This work was supported by the Russian Foundation for Basic Research (project nos. 13-02-01265a and 14-02-31051mol-a), by the Council of the President of the Russian Federation for Support of Young Scientists and Leading Scientific Schools (project no. NSh- 2886.2014.2), by the Presidium of the Russian Academy of Sciences (program no. 24.34), and by the Ministry of Education and Science of the Russian Federation (state contract no. 02.G25.31.0043 and state task for research at Siberian Federal University in 2014).
Предметные рубрики: RAY CIRCULAR-DICHROISM
YIELD
SPECTRA
Fe
Аннотация: The structural and magnetic properties of (Fe/Si) N nanostructures obtained by successive deposition on the SiO2/Si(100) surface at a temperature of the substrate of 300 K have been studied. The thicknesses of all Fe and Si layers have been determined by transmission electron microscopy measurements. The magnetic properties have been studied by the X-ray magnetic circular dichroism (XMCD) method near the Fe L 3, 2 absorption edges. The orbital (m l ) and spin (m S ) contributions to the total magnetic moment of iron have been separated. The thicknesses of magnetic and nonmagnetic iron silicide on the Si/Fe and Fe/Si interfaces have been determined with the surface sensitivity of the XMCD method and the model of the interface between the nonmagnetic and weakened magnetic phases.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Drokin N. A., Shabanov V. F.
Заглавие : Dielectric and optical properties of a 5-propyl-2-(p-cyanophenyl)-pyridine liquid crystal
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2003. - Vol. 45, Is. 4. - P797-801. - ISSN 1063-7834, DOI 10.1134/1.1569024
Примечания : Cited References: 12
Предметные рубрики: DECIMETER WAVELENGTH RANGE
SERIES
SPECTRA
5CB
Аннотация: The temperature dependences of the dielectric and optical parameters for a 5-propyl-2-(p-cyanophenyl)-pyridine (3CP) liquid crystal are investigated in the vicinity of the nematic-isotropic phase transition. The dielectric spectra of the 3CP compound in the crystalline, nematic, and isotropic phases are measured in the frequency range 1-1000 MHz, and the Debye approximations of the measured spectra are obtained. Analysis of the dependence of the static permittivity on the director orientation with respect to the direction of the electric pump field demonstrates that the angle between the dipole moment and the long axis of the molecule is approximately equal to 15degrees. (C) 2003 MAIK "Nauka / Interperiodica".
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Drokin N. A., Shabanov V. F.
Заглавие : Distribution function of relaxation times for a 4-n-pentyl-4 '-cyanobiphenyl liquid crystal
Разночтения заглавия :авие SCOPUS: Distribution function of relaxation times for a 4-n-pentyl-4′- cyanobiphenyl liquid crystal
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2005. - Vol. 47, Is. 9. - P1791-1796. - ISSN 1063-7834, DOI 10.1134/1.2045369
Примечания : Cited References: 15
Предметные рубрики: DIELECTRIC-RELAXATION
SPECTRA
INVERSION
Аннотация: The distribution function of relaxation times is reconstructed from the dielectric loss spectrum measured over a wide range of frequencies for a 4-n-pentyl-4'-cyanobiphenyl (5CB) liquid crystal. It is demonstrated that the distribution function for the isotropic and nematic phases is asymmetric in shape. Comparison shows that the reconstructed distribution function is in qualitative agreement with similar functions that are analytically derived from the Cole-Davidson and Havriliak-Negami empirical equations. The specific features observed in the behavior of the distribution function with a variation in the angle between the direction of polarization of a microwave electric field and the director of the liquid-crystal molecules are analyzed. A complex dependence of the permittivity for the liquid crystal in the range of ultrahigh frequencies is explained in terms of additional relaxation mechanisms associated with different motions of molecular fragments of alkyl chains. (c) 2005 Pleiades Publishing, Inc.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Drokin N. A., Poluboyarov V. A.
Заглавие : Impedance spectroscopy study of the electrical properties of cation-substituted barium hexaaluminate ceramics
Место публикации : Phys. Solid State. - 2018. - Vol. 60, Is. 2. - P.274-280. - ISSN 1063-7834, DOI 10.1134/S1063783418020063. - ISSN 1090-6460(eISSN)
Примечания : Cited References:18
Предметные рубрики: DIELECTRIC-RELAXATION
LIQUID-CRYSTALS
SPECTRA
Аннотация: We report on the behavior of frequency and temperature dependences of the impedance of a measuring cell in the form of a parallel-plate capacitor filled with barium hexaaluminate ceramics with four aluminum cations replaced by iron (BaO · 2Fe2O3 · 4Al2O3). The measurements have been performed in the frequency range of 0.5–108 Hz at temperatures of 20-375°C. A technique for determining the electrical properties of the investigated ceramics is proposed, which is based on an equivalent electric circuit allowing the recorded impedance spectra to be approximated with sufficiently high accuracy. The established spectral features are indicative of the presence of two electric relaxation times different from each other by three orders of magnitude. This fact is explained by the difference between the charge transport processes in the bulk of crystallites and thin intercrystallite spacers, for which the charge activation energies have been determined.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Churilov G. N., Korets A. Y., Titarenko Y. N.
Заглавие : Preparation of fullerenes and nanotubes in coal plasma jet in kilohertz frequency range
Место публикации : Zhurnal Tek. Fiz.: MEZHDUNARODNAYA KNIGA, 1996. - Vol. 66, Is. 1. - P191-194. - ISSN 0044-4642
Примечания : Cited References: 6
Предметные рубрики: SPECTRA
CARBON
WOS
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ekholm V., Chiuzbaian G. S., Sathe C., Nicolaou A., Guarise M., Simon M., Jaouen N., Luning J., Hague C. F., Gel'mukhanov F., Odelius M., Bjorneholm O., Rubensson, J-E
Заглавие : Core-hole localization and ultra-fast dissociation in SF6
Коллективы : Swedish Research Council (VR)Swedish Research Council; Russian Science FoundationRussian Science Foundation (RSF) [16-12-10109]
Место публикации : J. Phys. B. - 2020. - Vol. 53, Is. 18. - Ст.185101. - ISSN 0953-4075, DOI 10.1088/1361-6455/aba204. - ISSN 1361-6455(eISSN)
Примечания : Cited References: 36. - This work was supported by the Swedish Research Council (VR). The calculations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC). FG acknowledges support within the Russian Science Foundation (Project No. 16-12-10109)
Предметные рубрики: X-RAY-EMISSION
SYMMETRY-BREAKING
AB-INITIO
SPECTROSCOPY
SPECTRA
Аннотация: Resonant inelastic x-ray scattering spectra excited at the fluorine K resonances of SF6 have been recorded. While a small but significant propensity for electronically parity-allowed transitions is found, the observation of parity-forbidden electronic transitions is attributed to vibronic coupling that breaks the global inversion symmetry of the electronic wavefunction and localizes the core hole. The dependence of the scattering cross section on the polarization of the incident radiation and the scattering angle is interpreted in terms of local π/σ symmetry around the S–F bond. This symmetry selectivity prevails during the dissociation that occurs during the scattering process.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kazak N. V., Platunov M. S., Ivanova N. B., Knyazev Yu. V., Bezmaternykh L. N., Eremin E. V., Vasil'ev A. D., Bayukov O. A., Ovchinnikov S. G., Velikanov D. A., Zubavichus Y. V.
Заглавие : Crystal structure and magnetization of a Co3B2O6 single crystal
Место публикации : J. Exp. Theor. Phys.: MAIK Nauka-Interperiodica / Springer, 2013. - Vol. 117, Is. 1. - P.94-107. - ISSN 1063-7761, DOI 10.1134/S1063776113060186
Примечания : Cited References: 43. - The synchrotron measurements were performed at the Kurchatov Center of Synchrotron Radiation and Nanotechnologies (state contract no. 16.552.11.7055).This work was supported by the Russian Foundation for Basic Research (project nos. 12-02-00175-a, 12-02-90410-Ukr_a, 12-02-31543mol_a, 13-02-00958-a), the President of the Russian Federation (grant no. NSh-1044.2012.2), the Siberian Branch of the Russian Academy of Sciences (project no. 38), the Ministry of Education and Science of the Russian Federation (project no. 8365), and an integration project of SO RAN-NAN of Belarus (project no. 29).
Предметные рубрики: ABSORPTION FINE-STRUCTURE
NICKEL ORTHOBORATE
RAY
GDFE3(BO3)(4)
LUDWIGITE
NI3(BO3)2
NI3B2O6
SPECTRA
Аннотация: The crystal structure and magnetic properties of Co3B2O6 single crystals are studied. Orthorhombic symmetry with space group Pnnm is detected at room temperature. The measurements of static magnetization and dynamic magnetic susceptibility reveal two magnetic anomalies at T (1) = 33 K and T (2) = 10 K and an easy-axis magnetic anisotropy. The effective magnetic moment indicates a high-spin state of the Co2+ ion. A spin-flop transition is found at low temperatures and H (sf) = 23 kOe. EXAFS spectra of the K-edge absorption of Co are recorded at various temperatures, the temperature-induced changes in the parameters of the local environment of cobalt are analyzed, and the effective Co-Co and Co-O distances are determined. The magnetic interactions in the crystal are analyzed in terms of an indirect coupling model.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Slabko V. V., Tsipotan A. S. , Aleksandrovsky A. S., Slyusareva E. A.
Заглавие : Dynamics of self-organized aggregation of resonant nanoparticles in a laser field
Коллективы : Grant of the Ministry of Education and Science of the Russian Federation for Siberian Federal University; SB RAS Grant [24.31]; RFBR [14-02-00219 A]
Место публикации : Appl. Phys. B: Springer, 2014. - Vol. 117, Is. 1. - P.271-278. - ISSN 0946-2171, DOI 10.1007/s00340-014-5831-0. - ISSN 1432-0649
Примечания : Cited References: 30. - This research is partially supported by Grant of the Ministry of Education and Science of the Russian Federation for Siberian Federal University, by SB RAS Grant 24.31, and by RFBR Research Project No. 14-02-00219 A.
Предметные рубрики: PHOTOSTIMULATED AGGREGATION
SILVER
PRINCIPLES
PARTICLES
SPECTRA
SOLS
Аннотация: Self-organized aggregation of nanoparticles in external resonant laser field is considered using Brownian dynamics model. Formation probabilities are calculated for the pair of particles in dependence on laser wavelength and mutual orientation of particles. Times required for aggregation are calculated. Possibility of efficient aggregation using pulsed laser is deduced.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylova S. N., Gudim I. A., Aleksandrovsky A. S., Vtyurin A. N., Krylov A. S.
Заглавие : Electronic band structures of NdFe3(BO3)4 and NdGa3(BO3)4 crystals: ab initio calculations
Коллективы : Russian Foundation for Basic Research GrantRussian Foundation for Basic Research (RFBR) [20-42-240009]
Место публикации : Ferroelectrics. - 2021. - Vol. 575, Is. 1. - P.11-17. - ISSN 0015-0193, DOI 10.1080/00150193.2021.1888219. - ISSN 1563-5112(eISSN)
Примечания : Cited References: 27. - This work was supported by the Russian Foundation for Basic Research Grant No. 20-42-240009
Предметные рубрики: HOFE3(BO3)4
TEMPERATURE
SPECTRA
GROWTH
Аннотация: NdFe3(BO3)4 and NdGa3(BO3)4 crystals are of great interest due to their physical properties. For example, NdFe3(BO3)4 crystal demonstrates magnetodielectric and magnetopiezoelectric effects, and NdGa3(BO3)4 crystal possesses luminescent and nonlinear optical properties. In this work, the properties of these materials are calculated by the plane-wave pseudo-potential method based on density functional theory. The structures of the crystals are optimized. The electronic structure of NdFe3(BO3)4 and NdGa3(BO3)4 are calculated.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Antuzevics A., Rogulis U., Fedotovs A., Berzins D., Voronov V. N., Purans J.
Заглавие : EPR study of Gd3+ local structure in ScF3 crystal with negative thermal expansion coefficient
Место публикации : Phys. Scr.: IOP Publishing, 2015. - Vol. 90, Is. 11. - Ст.115801. - ISSN 0031-8949, DOI 10.1088/0031-8949/90/11/115801
Примечания : Cited References: 32. - We are grateful to Professor S Ovchinnikov for providing ScFINF3/INF samples. This work was supported by L-KC-11-0005 project Nr.KC/2.1.2.1.1/10/01/006,5.3
Предметные рубрики: ELECTRON-PARAMAGNETIC-RESONANCE
SPIN-HAMILTONIAN PARAMETERS
SINGLE-CRYSTALS
SUPERPOSITION-MODEL
CENTERS
SPECTRA
PHASE
TEMPERATURE
SIMULATION
Ключевые слова (''Своб.индексиров.''): electron paramagnetic resonance--gd3+--scf3--negative thermal expansion
Аннотация: Zero field splitting (ZFS) of Gd3+ impurity in ScF3 is studied by electron paramagnetic resonance at 77 and 295 K. ZFS parameter b4 values obtained from angular dependence simulations show that regardless of negative thermal expansion in ScF3 temperature dependence of |b4| is similar to other cubic fluoroperovskites. Our analysis of ZFS parameters indicates that the local structure of Gd3+ centres expands positively with temperature. © 2015 The Royal Swedish Academy of Sciences.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Myagkov V. G., Zhigalov V. S., Matsynin A. A., Bykova L. E., Mikhlin Y. L., Bondarenko G. N., Patrin G. S., Yurkin G. Yu.
Заглавие : Formation of ferromagnetic germanides by solid-state reactions in 20Ge/80Mn films
Место публикации : Thin Solid Films: Elsevier Science, 2014. - Vol. 552. - P.86-91. - ISSN 0040-6090, DOI 10.1016/j.tsf.2013.12.029
Примечания : Cited References: 53
Предметные рубрики: PHASE-FORMATION
MAGNETIC-PROPERTIES
Mn5Ge3 FILMS
X-RAY
Ge(111)
TRANSFORMATIONS
DIFFUSION
SPECTRA
SYSTEM
LAYERS
Ключевые слова (''Своб.индексиров.''): manganite-germanium--solid state reaction--first phase--mn5ge3 alloy--carbon impurity--oxygen impurity--annealing--magnetic anisotropy
Аннотация: Solid state reactions between Ge and Mn films are systematically examined using X-ray diffraction, photoelectron spectroscopy, and magnetic and electrical measurements. The films have a nominal atomic ratio Ge:Mn = 20:80 and are investigated at temperatures from 50 to 500 °C. It is established that after annealing at ~ 120°C, the ferromagnetic Mn5Ge3 phase is the first phase to form at the 20Ge/80Mn interface. As the annealing temperature increases to 300°C, the weak magnetic Mn5Ge 2 + Mn3Ge phases simultaneously begin to grow and they become dominant at 400°C. Increasing the annealing temperature to 500°C leads to the formation of the ferromagnetic phase with a Curie temperature TC ~ 350-360 K and magnetization 14-25 kA/m at room temperature. The X-ray diffraction study of the samples shows the reflections from the Mn 5Ge3 phase, and the photoelectron spectra contain the oxygen and carbon peaks. The homogeneous distribution of oxygen and carbon over the sample thickness suggests that the increased Curie temperature and magnetization are related to the migration of C and O atoms into the Mn 5Ge3 lattice and the formation of the Nowotny phase Mn5Ge3CxOy. The initiation temperature (~ 120 C) is the same in the Mn5Ge3 phase with the solid-state reactions in the Ge/Mn films as well as in the phase separation in the GexMn1 - x diluted semiconductors. Thus, we conclude that the synthesis of the Mn5Ge3 phase is the moving force for the spinodal decomposition of the GexMn 1 - x diluted semiconductors.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Malakhovskii A. V., Sukhachev A. L., Sokolov V. V., Gudim, I. A.
Заглавие : Giant natural circular dichroism of vibronic transitions in HoAl3(BO3)4
Место публикации : JETP Letters. - 2015. - Vol. 102, Is. 8. - P.493-495. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364015200084
Примечания : Cited References: 15. - This work was supported by the Council of the President of the Russian Federation for the Support of Leading Scientific Schools (project no. NSh-2886.2014.2).
Предметные рубрики: SINGLE-CRYSTAL
OPTICAL-ABSORPTION
SPECTRA
Ho3+
IONS
PR3+
Аннотация: The giant natural optical activity of vibronic replicas of the f–f5/8 → 5F2 transition in HoAl3(BO3)4 is observed. It exceeds the optical activity related to purely electronic transitions by two orders of magnitude and corresponds to the almost complete circular polarization of the transitions. This effect is explained by the local distortions of the crystal in the excited electronic state, which lead to the mixing of electron and vibrational wavefunctions and, as a consequence, to the delocalization of the vibronic wavefunction and the enhancement of spatial dispersion, which is responsible for the optical activity.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Flerov I. N., Tressaud A., Bogdanov E. V., Kartashev A. V., Bayukov O. A., Eremin E. V., Krylov A. S.
Заглавие : Heat capacity and magnetic properties of fluoride CsFe2+Fe3+F6 with defect pyrochlore structure
Место публикации : J. Solid State Chem. - 2016. - Vol. 237. - P.330-335. - ISSN 00224596 (ISSN), DOI 10.1016/j.jssc.2016.02.045
Примечания : Cited References: 19. - This study was partially supported by the Grant NSh-924.2014.2 of the President of the Russian Federation for the Support of Leading Scientific Schools.
Предметные рубрики: Crystal-structure
Mossbauer
CsFe2F6
Spectra
Ключевые слова (''Своб.индексиров.''): pyrochlore structure--phase transition--magnetic properties--thermal properties
Аннотация: Heat capacity, Mossbauer and Raman spectra as well as magnetic properties of fluoride CsFe2F6 with defect pyrochlore structure were studied. In addition to recently found above room temperature three successive structural transformations Pnma-Imma-I41amd-Fd-3m, phase transition of antiferromagnetic nature with the 13.7 K Neel temperature and a broad heat capacity anomaly with a maximum at about 30 K were observed. The room temperature symmetry Pnma is unchanged at least down to 7 K. Simple model of indirect bond used to estimate the exchange interactions and to propose a magnetic structure model. © 2016 Elsevier Inc. All rights reserved.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Tsikalov D. S.
Заглавие : Spin-wave resonance in gradient ferromagnets with concave and convex variations of magnetic parameters
Коллективы : Russian Foundation for Basic Research, Government of Krasnoyarsk Territory [18-42-243005]
Место публикации : J. Appl. Phys. - 2020. - Vol. 127, Is. 12. - Ст.123903. - ISSN 0021-8979, DOI 10.1063/1.5143499. - ISSN 1089-7550(eISSN)
Примечания : Cited References: 26. - This work was partially supported by the Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research project (No. 18-42-243005) "Synthesis and investigation of magnetic properties of gradient materials that are characterized by predetermined type of the magnetic parameter change" and the Krasnoyarsk Regional Fund of Science in the framework of participation in the conference "VII Euro-Asian Symposium 'Trends in MAGnetism' (EASTMAG 2019)."
Предметные рубрики: SPECTRA
MODES
Аннотация: The theory of spin-wave resonance in gradient ferromagnetic films with magnetic parameters varying in space described by both concave and convex quadratic functions is developed. Gradient structures such as a potential well, a potential barrier, and a monotonic change in potential between the film surfaces for both quadratic functions are considered. The waveforms of oscillations mn(z), the laws of the dependence of discrete frequencies ωn, and relative susceptibilities χn/χ01 of spin-wave resonances on the resonance number n are studied. It is shown that the law ωn∝n for nnc, where nc is the resonance level near the upper edge of the gradient inhomogeneity, which is well known for a parabolic potential well, is also valid for the potential barrier and for the monotonic change in potential, if these structures are formed by a concave quadratic function. It is shown that the law ωn∝(n−1/2)1/2, which we numerically derived and approximated by the analytical formula, is valid for all three structures formed by a convex quadratic function. It is shown that the magnetic susceptibility χn of spin-wave resonances for nnc is much greater than the susceptibility of resonances in a uniform film. An experimental study of both laws ωn(n) and χn(n) would allow one to determine the type of quadratic function that formed the gradient structure and the form of this structure. The possibility of creating gradient films with different laws ωn(n) and the high magnitude of the high-frequency magnetic susceptibility χn(n) at nnc make these metamaterials promising for practical applications.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylov A. S., Sofronova S. N., Kolesnikova E. M., Vtyurin A. N., Isaenko L. I.
Заглавие : Lattice dynamics of oxyfluoride Rb2KMoO3F3
Коллективы : International Symposium on Ferroic Domains and Micro- to Nanoscopic Structures, Russia/CIS/Baltic/Japan Symposium on Ferroelectricity
Место публикации : Ferroelectrics: Taylor & Francis LTD, 2012. - Vol. 441. - P.52-60. - ISSN 0015-0193, DOI 10.1080/00150193.2012.743791
Примечания : Cited References: 23
Предметные рубрики: PHASE-TRANSITIONS
RAMAN-SCATTERING
ELPASOLITE
CRYSTALS
DISORDER
SPECTRA
CS
Ключевые слова (''Своб.индексиров.''): oxyfluorides--lattice dynamics--ramam measurements
Аннотация: The complete Raman spectra of oxyfluoride Rb2KMoO 3F3 were obtained. At T ≈ 185 K phase transitions were found. Lattice dynamics of disordered structures of the investigated compound was simulated, and "soft" vibrational modes were found in the calculated spectrum. Copyright © Taylor & Francis Group, LLC.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Edelman I. S., Ivanova O. S., Ivantsov R. D., Velikanov D. A., Zabluda V. N., Zubavichus Y., Veligzhanin A. A., Zaikovskiy V. I., Stepanov S., Artemenko A., Curely J., Kliava J.
Заглавие : Magnetic nanoparticles formed in glasses co-doped with iron and larger radius elements
Место публикации : J. Appl. Phys.: American Institute of Physics, 2012. - Vol. 112, Is. 8. - Ст.84331. - P. - ISSN 0021-8979, DOI 10.1063/1.4759244
Примечания : Cited References: 65. - This work was partly supported by the Russian Foundation for Basic Research, Grant Nos. 07-02-92174 RFBR-CNRS and 11-02-00972, and President of Russia Federation Grant No NSh 1044.2012.2. A. Artemenko acknowledges financial support from the Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (EPREXINA, GA 255662). The synchrotron measurements were supported via the Russian federal Contract No. 16.552.11.7003. The authors thank K. P. Polyakova for the preparation of thin films.
Предметные рубрики: SUPERPARAMAGNETIC RESONANCE
FERROMAGNETIC-RESONANCE
TEMPERATURE-DEPENDENCE
FERRITE NANOPARTICLES
OXIDE NANOPARTICLES
FARADAY-ROTATION
CERAMICS
ANISOTROPY
PARTICLES
SPECTRA
Аннотация: A new type of nanoparticle-containing glasses based on borate glasses co-doped with low contents of iron and larger radius elements, Dy, Tb, Gd, Ho, Er, Y, and Bi, is studied. Heat treatment of these glasses results in formation of magnetic nanoparticles, radically changing their physical properties. Transmission electron microscopy and synchrotron radiation-based techniques: x-ray diffraction, extended x-ray absorption fine structure, x-ray absorption near-edge structure, and small-angle x-ray scattering, show a broad distribution of nanoparticle sizes with characteristics depending on the treatment regime; a crystalline structure of these nanoparticles is detected in heat treated samples. Magnetic circular dichroism (MCD) studies of samples subjected to heat treatment as well as of maghemite, magnetite, and iron garnet allow to unambiguously assign the nanoparticle structure to maghemite, independently of co-dopant nature and of heat treatment regime used. Different features observed in the MCD spectra are related to different electron transitions in Fe3+ ions gathered in the nanoparticles. The static magnetization in heat treated samples has non-linear dependence on the magnetizing field with hysteresis. Zero-field cooled magnetization curves show that at higher temperatures the nanoparticles occur in superparamagnetic state with blocking temperatures above 100 K. Below ca. 20 K, a considerable contribution to both zero field-cooled and field-cooled magnetizations occurs from diluted paramagnetic ions. Variable-temperature electron magnetic resonance (EMR) studies unambiguously show that in as-prepared glasses paramagnetic ions are in diluted state and confirm the formation of magnetic nanoparticles already at earlier stages of heat treatment. Computer simulations of the EMR spectra corroborate the broad distribution of nanoparticle sizes found by "direct" techniques as well as superparamagnetic nanoparticle behaviour demonstrated in the magnetization studies. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759244]
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shtarev D. S., Shtareva, A., V, Kevorkyants R., Rudakova, A., V, Molokeev M. S., Bakiev, T., V, Bulanin K. M., Ryabchuk V. K., Serpone N.
Заглавие : Materials synthesis, characterization and DFT calculations of the visible-light-active perovskite-like barium bismuthate Ba1.264(4)Bi1.971(4)O4 photocatalyst
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [19-73-10013]; Saint-Petersburg State University [39054581]; Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [18-03-00855]
Место публикации : J. Mater. Chem. C. - 2020. - Vol. 8, Is. 10. - P.3509-3519. - ISSN 2050-7526, DOI 10.1039/c9tc06457e. - ISSN 2050-7534(eISSN)
Примечания : Cited References: 42. - The current research was kindly funded by a grant from the Russian Science Foundation (project No. 19-73-10013). R. K., A. V. R., V. K. R. and T. V. B. acknowledge financial support from Saint-Petersburg State University (Pure ID 39054581). A. V. R. thanks the Russian Foundation for Basic Research for a Grant No. 18-03-00855 that supported studies into the photoinduced hydrophilicity of the bismuthate. The authors are further grateful to the staff of the Khabarovsk Innovation and Analytical Center of the Yu. A. Kosygin Institute of Tectonics and Geophysics of the Far Eastern Branch of the Russian Academy of Sciences, and the Resource Centers of the Research Park at the Saint-Petersburg State University: (i) the Center for Diagnostics of Functional Materials for Medicine, Pharmacology and Nanoelectronics, (ii) the Center for Physical Methods of Surface Investigation, (iii) the Center for Optical and Laser Materials Research, and the laboratories of (iv) Nanotechnology and (v) Nanophotonics for their valuable assistance in carrying out the research and in providing the needed equipment. One of us (N.S.) is grateful to Prof. Angelo Albini and the staff of the PhotoGreen Laboratory at the University of Pavia, Italy, for their continued hospitality.
Предметные рубрики: OXIDE
NIO/SRBI2O4
SPECTRA
DRIVEN
CO2
LA
Аннотация: A perovskite-like barium bismuthate of the BaBi2O4 class, Ba1.264(4)Bi1.971(4)O4, has been prepared by solid-state synthesis and subsequently characterized by a number of experimental techniques (XPS, DRS, SEM, EDX and Raman spectroscopy), as well as by a DFT computational approach using the GGA Perdew–Burke–Ernzerhof (PBE) density functional to determine the energy band structure. XRD peaks were indexed to a rhombohedral cell (R[3 with combining macron]m) with parameters close to Ba0.156Bi0.844O1.422 (i.e., to Ba0.439Bi2.374O4), which upon Rietveld refinement gave Ba1.264(4)Bi1.971(4)O4. The Bi–O bond lengths determined from this refinement (1.86 and 2.31 Å) accorded with the bond lengths estimated from Raman spectra (1.97 and 2.26 Å). DFT calculations revealed the bismuthate to display two bandgaps that correspond to lower-energy indirect (2.28 eV) and to higher-energy direct (2.36 eV) electronic transitions in good agreement with the experimental bandgaps of 2.26 eV and 2.43 eV, respectively, from Tauc plots of DRS spectra. Relative to the indirect bandgap energy of 2.26 eV, the energies of the valence band and of the conduction band were, respectively, +1.14 eV and −1.12 eV. The photoactivity of Ba1.264(4)Bi1.971(4)O4 was examined toward the photoreduction of the greenhouse gas CO2 in aqueous media photoelectrochemically yielding alcohols and alkanes, while in the gas phase in an infrared cell reactor the products were carbon monoxide and alkanes.
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