Библиотека института физики им. Л.В. Киренского СО РАН

Главная

Базы данных

Труды сотрудников ИФ СО РАН - результаты поиска

Вид поиска

Каталог книг и брошюр библиотеки ИФ СО РАН

Каталог журналов библиотеки ИФ СО РАН

Труды сотрудников ИФ СО РАН

Область поиска

в найденном

Формат представления найденных документов:
полный	информационный	краткий

Отсортировать найденные документы по:
автору	заглавию	году издания	типу документа

Поисковый запрос: (<.>S=Iron<.>)

Общее количество найденных документов : 30
Показаны документы с 1 по 20

1-20 21-30

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrichkov V. A., Polukeev S. I., Ovchinnikov S. G.
Заглавие : Cation spin and superexchange interaction in oxide materials below and above spin crossover under high pressure
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [18-12-00022]
Место публикации : Phys. Rev. B. - 2020. - Vol. 101, Is. 9. - Ст.094409. - ISSN 2469-9950, DOI 10.1103/PhysRevB.101.094409. - ISSN 2469-9969(eISSN)
Примечания : Cited References: 65. - We acknowledge the support of the Russian Science Foundation through Grant No. 18-12-00022
Предметные рубрики: EXCHANGE INTERACTION
PHASE-TRANSITIONS
STATE
ELECTRON
IRON
Аннотация: We derived simple rules for the sign of 180° superexchange interaction based on the multielectron calculations of the superexchange interaction in the transition metal oxides that are valid both below and above spin crossover under high pressure. The superexchange interaction between two cations in dn configurations is given by a sum of partial contributions related to the electron-hole virtual excitations to the different states of the dn+1 and dn−1 configurations. Using these rules, we have analyzed the sign of the 180° superexchange interaction of a number of oxides with magnetic cations in electron configurations from d2 until d8: the iron, cobalt, chromium, nickel, copper, and manganese oxides with increasing pressure. The most interesting result concerns the magnetic state of cobalt and nickel oxides CoO, Ni2O3 and also La2CoO4, LaNiO3 isostructural to well-known high-TC and colossal magnetoresistance materials. These oxides have a spin 12 at the high pressure. Change of the interaction from antiferromagnetic below spin crossover to ferromagnetic above spin crossover is predicted for oxide materials with cations in d5(FeBO3) and d7(CoO) configurations, while for materials with the other dn configurations spin crossover under high pressure does not change the sign of the 180∘ superexchange interaction.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kremneva A. M., Fedorov A. V., Bulavchenko O. A., Knyazev Yu. V., Saraev A. A., Yakovlev V. A., Kaichev V. V.
Заглавие : Effect of calcination temperature on activity of Fe2O3-Al2O3 nanocomposite catalysts in CO oxidation
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [17-73-20157]; National center of investigation of catalysts" at Boreskov Institute of Catalysis
Место публикации : Catal. Lett. - 2020. - Vol. 150. - P.3377-3385. - ISSN 1011-372X, DOI 10.1007/s10562-020-03250-8. - ISSN 1572-879X(eISSN)
Примечания : Cited References: 31. - This work was supported by the Russian Science Foundation (Grant No. 17-73-20157). The experiments were performed using facilities of the shared research center "National center of investigation of catalysts" at Boreskov Institute of Catalysis. The authors thank A.Yu. Gladky for the TPR measurements and Z.S. Vinokurov for the XRD measurements.
Предметные рубрики: MOSSBAUER
SPECTROSCOPY
CHEMISTRY
IRON
XPS
ADSORPTION
OXYGEN
FE
Аннотация: Nanocomposite Fe–Al oxide catalysts were prepared by the melting of iron and aluminum nitrates with the subsequent calcination in air at different temperatures. It was found that the catalysts calcined at 450 °C are more active in the oxidation of CO than the catalysts calcined at 700 °C. X-ray diffraction and X-ray photoelectron spectroscopy showed that all the catalysts consist of hematite, α-Fe2O3 nanoparticles, and Al2O3 in an amorphous state. Iron oxide is the active component, which provides the oxidation of CO, while alumina is a texture promoter. The increase in the calcination temperature leads to a minor increase in the average size of hematite nanoparticles and an insignificant decrease in the specific surface area. Kinetic measurements showed that the oxidation of CO over the Fe–Al catalysts calcined at 450 and 700 °C proceeds with the activation energy of 61–69 and 91 kJ/mol, respectively. This means that the low-temperature and high-temperature catalysts contain different active species. Temperature-programmed reduction with CO indicated that the decrease in the calcination temperature improves the reducibility of the Fe-Al nanocomposites. According to 57Fe Mössbauer spectroscopy, the low-temperature catalysts contain hydrated iron oxides (acagenite and ferrihydrite) and a significant amount of highly defective hematite, which is absent in the high-temperature catalyst. These species can provide the enhanced activity of the low-temperature catalysts in the oxidation of CO.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Grishina, Svetlana, Kodera, Peter, Goryainov, Sergey, Oreshonkov A. S., Seryotkin, Yurii, Simko, Frantisek, Polozov, Alexander G.
Заглавие : Application of Raman spectroscopy for identification of rinneite (K3NaFeCl6) in inclusions in minerals
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [18-05-00682]; European Regional Development FundEuropean Union (EU) [ITMS 26240220086]; Vedecka Grantova Agentura MSVVaS SR a SAV [1/0313/20]
Место публикации : J. Raman Spectrosc. - 2020. - Vol. 51, Is. 12. - P.2505-2516. - ISSN 0377-0486, DOI 10.1002/jrs.6005. - ISSN 1097-4555(eISSN)
Примечания : Cited References: 55. - Russian Foundation for Basic Research, Grant/Award Numbers: 18-05-00682, 18-05-00682; European Regional Development Fund, Grant/Award Number: ITMS 26240220086; Vedecka Grantova Agentura MSVVaS SR a SAV, Grant/Award Number: 1/0313/20
Предметные рубрики: SALT MELT
IRON
DEPOSIT
FLUIDS
TRANSFORMATIONS
FERRIHYDRITE
Аннотация: Solid daughter phases in fluid and salt melt inclusions in minerals provide important clues to characterization of mineral‐forming processes. The analysis of the fluid inclusions often requires the exposure of the daughter minerals. Rinneite (K3NaFeCl6), which is a hygroscopic mineral, decomposes in air and cannot thus be identified by conventional methods. A combined approach has been applied for investigation of synthetic and natural rinneite to acquire its diagnostic Raman spectrum for a nondestructive identification. We used natural rinneite inclusions in halite, suitable for applying a complex of methods, to clear up the reference spectrum. Improved high‐resolution X‐ray diffraction (XRD) data obtained from natural rinneite inclusion are comparable with that of previously published, with similar unit cell dimensions. Polarized Raman spectra of natural inclusions were obtained using different geometries and polarization of the incident and scattered light. Interpretation of experimental Raman spectra was performed within the framework of lattice dynamics simulations and group analysis. Individual spectral bands are interpreted in terms of Raman‐active vibrational modes of K3NaFeCl6 structural units. Raman spectrum of synthetic rinneite with main peaks at 75, 91, 103, 143, 167, 171, 187, and 239 cm−1 agrees well with the spectra of rinneite inclusions in halite from the Nepa potash deposit and rinneite daughter minerals in salt melt inclusions hosted by quartz veinlets from the porphyry gold systems in the Central Slovakia Volcanic Field. This provides a firm basis for any future identification of this mineral worldwide, using nondestructive Raman spectroscopy.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из сборника (выпуск монографической серии)
Шифр издания :
Автор(ы) : Igumenov, A. Yu, Parshin A. S., Kanzychakova V. O., Demin A. M., Andryushchenko T. A., Mikhlin, Yu L., Pehelyakov O. P., Zhigalov V. S.
Заглавие : Factor analysis of inelastic electron scattering cross section spectra of FeSi2
Коллективы : International Scientific Conference Reshetnev Readings
Место публикации : IOP Conf. Ser.: Mater. Sci. Eng. - 2019. - Vol. 467: 21st International Scientific Conference Reshetnev Readings-2017. - Ст.012010. - , DOI 10.1088/1757-899X/467/1/012010
Примечания : Cited References: 21
Предметные рубрики: ENERGY-LOSS SPECTROSCOPY
IRON
Аннотация: Iron disilicide is widely used in creation of such nanotechnology devices as photoelectric converters. The investigation of iron silicide FeSi2 with the method of inelastic electron scattering cross-section spectroscopy was carried out. The decomposition of inelastic electron scattering cross-section spectra of FeSi2 to bulk and surface energy loss components using factor analysis was carried out. The amplitude of energy loss components can be used for identification of their origin.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuz'min V. I., Orlov Yu. S., Zarubin A. E., Ovchinnikova T. M., Ovchinnikov S. G.
Заглавие : Magnetism in spin crossover systems: Short-range order and effects beyond the Heisenberg model
Коллективы : Russian Scientific FoundationRussian Science Foundation (RSF) [18-12-00022]
Место публикации : Phys. Rev. B. - 2019. - Vol. 100, Is. 14. - Ст.144429. - ISSN 2469-9950, DOI 10.1103/PhysRevB.100.144429. - ISSN 2469-9969(eISSN)
Примечания : Cited References: 72. - The authors thank the Russian Scientific Foundation for the financial support under Grant No. 18-12-00022.
Предметные рубрики: LOWER-MANTLE
STATE
TRANSITION
PRESSURE
IRON
SUSCEPTIBILITY
Аннотация: To study non-Heisenberg effects in the vicinity of spin crossover in strongly correlated electron systems we derive an effective low-energy Hamiltonian for the two-band Kanamori model. It contains a Heisenberg high-spin term proportional to exchange constant as well as a low-spin term proportional to spin gap parameter ɛs. Using cluster mean field theory we obtain several non-Heisenberg effects. Near the critical value of spin gap ɛcs there is a magnetic phase transition of first order. In the vicinity of ɛcs in the paramagnetic phase we observe nontrivial behavior of the Curie constant in the paramagnetic susceptibility in the wide range of temperature. Reentrant temperature behavior of nearest-neighbor spin-spin correlations is observed at ɛsɛcs. Finally, the pressure-temperature magnetic phase diagram for ferroperriclase is obtained using the effective Hamiltonian.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pavlovskiy M. S., Zinenko V. I., Shinkorenko A. S.
Заглавие : Effect of a rare-earth ion on the structural instability in RFe3(BO3)4 crystals
Коллективы : Russian Science Foundation [17-72-10122]
Место публикации : JETP Letters. - 2018. - Vol. 108, Is. 2. - P.116-120. - ISSN 0021-3640, DOI 10.1134/S0021364018140114. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 17. - This work was supported by the Russian Science Foundation (project no. 17-72-10122).
Предметные рубрики: Iron
GdFe3(BO3)4
Аннотация: The dynamics of the crystal lattice of RFe3(BO3)4 (R = Pr, Nd, Sm, Gd, Tb, Dy, and Ho) compounds in the high-symmetry R32 phase has been calculated. Significant changes in spectra of compounds with various rare-earth ions have been obtained only near the edge Λ point of the Brillouin zone (qΛ = 1/3(−2b1 + b2 + b3, where b1, b2, and b3 are the reciprocal lattice vectors) for acoustic oscillation branches. A decrease in the frequency of an acoustic mode at the point Λ has been revealed in all studied compounds. This frequency depends on the type of rare-earth ion and decreases from a compound with Pr to a compound with Ho down to imaginary values. Such a behavior of the frequency of the unstable acoustic mode is in good agreement with experimental data on the dependence of the temperature of the R32 → P3121 structural phase transition on the type of rare-earth ion in ferroborates.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Yakushkin S. S., Dubrovskii A. A., Bukhtiyarova G. A., Shaikhutdinov K. A., Martyanov O. N.
Заглавие : Study of the high-coercivity material based on ε-Fe2O3 nanoparticles in the silica gel matrix
Место публикации : Tech. Phys. Lett.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 42, Is. 4. - P.347-350. - ISSN 10637850 (ISSN), DOI 10.1134/S1063785016040039
Примечания : Cited References: 17. - This study was supported by the Federal Agency for Scientific Organizations of Russia (base budget financing no. V.44.1.15), the Scientific and Educational Center of Energy-Efficient Catalysis at the Novosibirsk State University, and the Russian Foundation for Basic Research (project no. 15-32-50919).
Предметные рубрики: Phase
Field
State
Oxide
Iron
Аннотация: We report the results of investigations of ε-Fe2O3 magnetic nanoparticles obtained by incipient wetness impregnation of silica gel. It was established that the obtained samples with an iron content of 12‒16% mass % containing ε-Fe2O3 nanoparticles with an average size of 10 nm on the silica gel surface exhibit a room-temperature coercivity of about 10 kOe. Along with fabrication simplicity, this fact makes the prepared samples promising for application as a magnetically hard material. © 2016, Pleiades Publishing, Ltd
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Korshunov M. M., Togushova Yu. N., Dolgov O. V.
Заглавие : Uniform impurity scattering in two-band s ± and s ++ superconductors
Коллективы : RFBR [16-02-00098]; Leading Scientific Schools of the Russian Federation [NSh-2886.2014.2]
Место публикации : J. Supercond. Nov. Magn.: Springer, 2016. - Vol. 29, Is. 4. - С. 1089-1095. - ISSN 1557-1939, DOI 10.1007/s10948-016-3385-6. - ISSN 1557-1947(eISSN)
Примечания : Cited References:28. - We are grateful to D.V. Efremov and A. A. Golubov for useful discussions. We acknowledge the partial support by RFBR (Grant 16-02-00098) and President Grant for Government Support of the Leading Scientific Schools of the Russian Federation (NSh-2886.2014.2).
Предметные рубрики: High-temperature superconductivity
Iron
Ключевые слова (''Своб.индексиров.''): multiband superconductivity--impurity scattering--fe-based--superconductors
Аннотация: The s ± and s ++ models for the superconducting state are subject of intense studies regarding Fe-based superconductors. Depending on the parameters, disorder may leave intact or suppress T c in these models. Here, we study the special case of disorder with equal values of intra- and interband impurity potentials in the two-band s ± and s ++ models. We show that this case can be considered as an isolated point and T c there has maximal damping for a wide range of parameters.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parshin A. S., Igumenov A. Y., Mikhlin Y. L., Pchelyakov O. P., Zhigalov V. S.
Заглавие : Comparative analysis of characteristic electron energy loss spectra and inelastic scattering cross-section spectra of Fe
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 58, Is. 5. - P.908-914. - ISSN 10637834 (ISSN), DOI 10.1134/S106378341605019X
Примечания : Cited References: 29
Предметные рубрики: Loss-spectroscopy
Quantitative-analysis
Iron
Si
Ge
Аннотация: The inelastic electron scattering cross section spectra of Fe have been calculated based on experimental spectra of characteristic reflection electron energy loss as dependences of the product of the inelastic mean free path by the differential inelastic electron scattering cross section on the electron energy loss. It has been shown that the inelastic electron scattering cross-section spectra have certain advantages over the electron energy loss spectra in the analysis of the interaction of electrons with substance. The peaks of energy loss in the spectra of characteristic electron energy loss and inelastic electron scattering cross sections have been determined from the integral and differential spectra. It has been shown that the energy of the bulk plasmon is practically independent of the energy of primary electrons in the characteristic electron energy loss spectra and monotonically increases with increasing energy of primary electrons in the inelastic electron scattering cross-section spectra. The variation in the maximum energy of the inelastic electron scattering cross-section spectra is caused by the redistribution of intensities over the peaks of losses due to various excitations. The inelastic electron scattering cross-section spectra have been analyzed using the decomposition of the spectra into peaks of the energy loss. This method has been used for the quantitative estimation of the contributions from different energy loss processes to the inelastic electron scattering cross-section spectra of Fe and for the determination of the nature of the energy loss peaks. © 2016, Pleiades Publishing, Ltd.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Togushova, Yu. N., Shestakov V. A., Korshunov M. M.
Заглавие : Impurity-induced smearing of the spin resonance peak in Fe-based superconductors
Коллективы : RFBR [13-02-01395]; President Grant for Government Support of the Leading Scientific Schools of the Russian Federation [NSh-2886.2014.2]; Ministry of education and science of Russia [GF-2, SFU]
Место публикации : J. Low Temp. Phys.: Springer/Plenum Publishers, 2016. - Vol. 185, Is. 5-6. - P.481-487. - ISSN 0022-2291, DOI 10.1007/s10909-016-1577-x. - ISSN 1573-7357(eISSN)
Примечания : Cited References:25. - We acknowledge partial support by the RFBR (Grant 13-02-01395), President Grant for Government Support of the Leading Scientific Schools of the Russian Federation (NSh-2886.2014.2), and The Ministry of education and science of Russia (GF-2, SFU).
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTIVITY
ELECTRONIC-STRUCTURE
IRON
Ключевые слова (''Своб.индексиров.''): fe-based superconductors--spin resonance peak--spin-orbit coupling--impurity scattering
Аннотация: The spin resonance peak in the iron-based superconductors is observed in inelastic neutron scattering experiments and agrees well with predicted results for the extended s-wave (s±) gap symmetry. On the basis of four-band and three-orbital tight-binding models we study the effect of nonmagnetic disorder on the resonance peak. Spin susceptibility is calculated in the random-phase approximation with the renormalization of the quasiparticle self-energy due to the impurity scattering in the static Born approximation. We find that the spin resonance becomes broader with the increase of disorder and its energy shifts to higher frequencies. For the same amount of disorder the spin response in the s± state is still distinct from that of the s++ state.
Смотреть статью,
WOS,
Читать в сети ИФ
Найти похожие

11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Smirnova E. S., Alekseeva O. A., Dudka A. P., Verin I. A., Artemov V. V., Bezmaternykh L. N., Gudim I. A., Frolov K. V., Lyubutin I. S.
Заглавие : Structure of Gd0.95Bi0.05Fe3(BO3)4single crystals at 293 and 90 K
Место публикации : Crystallogr. Rep.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 61, Is. 4. - P.558-565. - ISSN 10637745 (ISSN), DOI 10.1134/S1063774516040192
Примечания : Cited References: 27. - This study was performed using the equipment of the Center of Collective Use of the Shubnikov Institute of Crystallography of the Russian Academy of Sciences and it was supported by the Ministry of Education and Science of the Russian Federation (Project RFMEFI62114X0005) and in part by the Russian Foundation for Basic Research (Grant nos. 14-02-00483 and 14-02-00307) and the Federal Program on Support of Leading Scientific Schools (Grant no. NSh-6617.2016.5).
Предметные рубрики: TRIGONAL GdFe3(BO3)4
PHASE-TRANSITIONS
IRON
Аннотация: The structure of GdFe3(BO3)4 single crystals has been studied by X-ray diffraction at 293 and 90 K. The crystals are grown from a flux in the Bi2Mo3O12–B2O3–Li2MoO4–Gd2O3–Fe2O3 system. The results of chemical analysis and structural study show that these crystals contain bismuth as an impurity. It is found that bismuth atoms are located at gadolinium sites in the structure. A decrease in the temperature is accompanied by a lowering of the symmetry from sp. gr. R32 (at 293 K) to sp. gr. P3121 (at 90 K). The presence of two types of iron chains with different geometries at 90 K promotes a change in the magnetic properties of these crystals with a decrease in the temperature. © 2016, Pleiades Publishing, Inc.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bataleva Yu. V., Palyanov Y. N., Borzdov Y. M., Bayukov O. A., Sobolev N. V.
Заглавие : The formation of graphite upon the interaction of subducted carbonates and sulfur with metal-bearing rocks of the lithospheric mantle
Место публикации : Dokl. Earth Sci.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 466, Is. 1. - P.88-91. - ISSN 1028334X (ISSN), DOI 10.1134/S1028334X16010190
Примечания : Cited References: 15. - This study was supported by the Russian Science Foundation (project no. 14-27-00054).
Предметные рубрики: Diamond formation
Silicon
Iron
Аннотация: Experimental studies of the Fe0–(Mg, Ca)CO3–S system were carried out during 18–20 h at 6.3 GPa, 900–1400°C. It is shown that the major processes resulting in the formation of free carbon include reduction of carbonates upon redox interaction with Fe0 (or Fe3C), extraction of carbon from iron carbide upon interaction with a sulfur melt/fluid, and reduction of the carbonate melt by Fe–S and Fe⎯S–C melts. Reconstruction of the processes of graphite formation indicates that carbonates and iron carbide may be potential sources of carbon under the conditions of subduction, and participation of the sulfur melt/fluid may result in the formation of mantle sulfides. © 2016, Pleiades Publishing, Ltd.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bartolome J., Badía-Romano L., Rubin J., Bartolome F., Varnakov S. N., Ovchinnikov S. G., Burgler D.E.
Заглавие : Magnetic properties, morphology and interfaces of (Fe/Si)n nanostructures
Коллективы : International Conference on Magnetism
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 400. - P.271-275. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2015.07.046
Примечания : Cited References: 43. - The financial support of the Spanish MINECOMAT2011-23791 and MAT2015-53921-R, Aragonese DGA-IMANAE34 (cofounded by Fondo Social Europeo) and European FEDER funds is acknowledged. Program of the President of the Russian Federation for the support of leading scientific schools (Scientific School 2886.2014.2), RFBR (Grant no. 13-02-01265), the Ministry of Education and Science of the Russian Federation (State contract no. 02.G25.31.0043 and State task no. 16.663.2014К)
Предметные рубрики: INTERLAYER EXCHANGE
Fe/Si(100) INTERFACE
SILICIDE FORMATION
ULTRAHIGH-VACUUM
FILMS
IRON
MAGNETORESISTANCE
SUPERLATTICES
SPECTROSCOPY
DEPOSITION
Аннотация: A systematic study of the iron–silicon interfaces formed upon preparation of (Fe/Si) multilayers has been performed by the combination of modern and powerful techniques. Samples were prepared by molecular beam epitaxy under ultrahigh vacuum onto Si wafers or single crystalline Ag(100) buffer layers grown on GaAs(100). The morphology of these films and their interfaces was studied by a combination of scanning transmission electron microscopy, X-ray reflectivity, angle resolved X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy. The Si-on-Fe interface thickness and roughness were determined to be 1.4(1) nm and 0.6(1) nm, respectively. Moreover, determination of the stable phases formed at both Fe-on-Si and Si-on-Fe interfaces was performed using conversion electron Mössbauer spectroscopy on multilayers with well separated Si-on-Fe and Fe-on-Si interfaces. It is shown that while a fraction of Fe remains as α-Fe, the rest has reacted with Si, forming the paramagnetic FeSi phase and a ferromagnetic Fe rich silicide. We conclude that there is an identical paramagnetic c-Fe1−xSi silicide sublayer in both Si-on-Fe and Fe-on-Si interfaces, whereas an asymmetry is revealed in the composition of the ferromagnetic silicide sublayer.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Komogortsev S. V., Iskhakov R. S., Zimin A. A., Filatov E. Y., Korenev S. V., Shubin Yu. V., Chizhik N. A., Yurkin G. Yu., Eremin E. V.
Заглавие : The exchange interaction effects on magnetic properties of the nanostructured CoPt particles
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 401. - P.236-241. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2015.10.041
Примечания : Cited References: 55. - The work has been partially supported by RFBR Grants 15-08-06673, 14-03-00411, 14-03-00129, 15-42-0417115 and it is partly performed in Siberian Federal University within the state contract of the Russian Federation Ministry of Education and Science for 2014-2016 (project number 1792)
Предметные рубрики: CLUSTER BEAM DEPOSITION
BULK MAGNETS
NANOCRYSTALLINE FERROMAGNETS
REMANENCE ENHANCEMENT
THIN-FILMS
COERCIVITY
MICROSTRUCTURE
NANOPARTICLES
IRON
SYSTEM
Аннотация: Various manifestations of the exchange interaction effects in magnetization curves of the CoPt nanostructured particles are demonstrated and discussed. The inter-grain exchange constant A in the sponge-like agglomerates of crystallites is estimated as A=(7±1) pJ/m from the approach magnetization to saturation curves that is in good agreement with A=(6.6±0.5) pJ/m obtained from Bloch T 3/2 law. The fractal dimensionality of the exchange coupled crystallite system in the porous media of the disordered CoPt alloy d=(2.60±0.18) was estimated from the approach magnetization to saturation curve. Coercive force decreases with temperature as Hc~T 3/2 which is assumed to be a consequence of the magnetic anisotropy energy reduction due to the thermal spin wave excitations in the investigated CoPt particles. © 2015 Elsevier B.V. All rightsreserved.Демонстрируются и обсуждаются различные проявления эффектов обменного взаимодействия в кривых намагниченности наноструктуированных частиц CoPt. Межзеренная обменная константа А в агломератах губчатой структуры кристаллитов оценивается как /A/=(7±1) pJ/m из кривых приближения намагниченности к насыщению, это значение находится в хорошем согласии с /A/=(6.6±0.5) pJ/m, полученным из закона /T/. /2 Блоха. Размерность фрактала обменно-соединенных кристаллических систем в пористой среды неупорядоченного сплава CoPt /d/=(2.60±0.18) оценивалась из кривых приближения намагниченности к насыщению. Коэрцитивная сила уменьшается с температурой по закону /H_c /~/T/. /2 , который, как предполагается, есть следствие уменьшения энергии магнитной анизотропии из-за теплового возбуждения спиновых волн в изучаемых частицах CoPt.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Anshits A. G., Bayukov O. A., Anshits N. N., Pletnev O. N., Rabchevskii E. V., Vereshchagin S. N., Kondratenko E. V.
Заглавие : Nature of the active sites of ferrospheres in the oxidative condensation of methane
Коллективы : Russian Science Foundation [4-13-00289], Russian Congress on Catalysis (2; 2014 ; Oct. ; 2–5; Samara)
Место публикации : Kinet. Catal.: MAIK Nauka-Interperiodica / Springer, 2015. - Vol. 56, Is. 4. - P.523-531. - ISSN 0023, DOI 10.1134/S0023158415040023. - ISSN 16083210(eISSN)
Примечания : Cited References:37. - This work was supported by the Russian Science Foundation (grant no. 14-13-00289).
Предметные рубрики: GLASS CRYSTAL CATALYSTS
HIGH-TEMPERATURE
MOSSBAUER
MAGNETITES
MICROSPHERES
SELECTIVITY
CONVERSION
FERRITES
ASHES
IRON
Ключевые слова (''Своб.индексиров.''): oxidative condensation of methane--ferrospheres--iron spinel--mossbauer spectroscopy--structural defects
Аннотация: The catalytic properties of ferrospheres containing 76–97 wt % Fe2O3 in the oxidative condensation of methane were compared with their phase composition and the distribution of iron cations over the crystallographic positions of iron-containing phases in a steady state. It was established that the reaction route of methane oxidation changed at a Fe2O3 content of 89 wt %. Deep oxidation was the main reaction route on ferrospheres with a Fe2O3 content of 88.8 wt %. At a Fe2O3 content of ≥89 wt %, the yield of C2 hydrocarbons sharply increased and the contribution of deep oxidation decreased. The yield of C2 hydrocarbons correlated with the amount of defects in the structure of iron spinel, which are iron ions with the tetrahedral cation of Ca2+ and the octahedral cation vacancy among the nearest neighbors.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Ovchinnikova T. M., Plotkin V. V., Dyad'kov P. G.
Заглавие : Spin crossover and Mott-Hubbard transition under high pressure and high temperature in the low mantle of the Earth
Коллективы : International conference on interaction of intense energy fluxes , International Conference on Interaction of Intense Energy Fluxes with Matter (XXX; 1–6 March 2015; Elbrus, Kabardino-Balkaria, Russia)
Место публикации : J. Phys.: Conf. Ser./ International conference on interaction of intense energy fluxes (30 ; 2015 ; March ; 01-06): IOP Publishing, 2015. - Vol. 653. - Ст.012095. - ISSN 1742-6588, DOI 10.1088/1742-6596/653/1/012095
Примечания : Cited References:22
Предметные рубрики: PHASE-TRANSITION
GEOMAGNETIC DATA
MAGNESIOWUSTITE
IRON
METALLIZATION
LAYER
Аннотация: Effect of high pressure induced spin crossover on the magnetic, electronic and structural properties of the minerals forming the Earth's low mantle is discussed. The low temperature P, T phase diagram of ferropericlase has the quantum phase transition point P = 56 GPa at T = 0 confirmed recently by the synchrotron Mossbauer spectroscopy. The LDA+GTB calculated phase diagram describes the experimental data. Its extension to the high temperature resulted earlier in prediction of the metallic properties of the Earth's mantle at the depth 1400 km h 1800 km. Estimation of the electrical conductivity based on the percolation theory is given. We discuss also the thermodynamic properties and structural anomalies resulting from the spin crossover and metal insulator transition and compare them with the experimental seismic and geomagnetic field data.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Dubrovskiy A. A., Balaev A. D., Shaykhutdinov K. A., Bayukov O. A., Pletnev O. N., Yakushkin S. S., Bukhtiyarova G. A., Martyanov O. N.
Заглавие : Size effects in the magnetic properties of ε-Fe2O3 nanoparticles
Место публикации : J. Appl. Phys.: American Institute of Physics, 2015. - Vol. 118, Is. 21. - Ст.213901. - ISSN 00218979 (ISSN), DOI 10.1063/1.4936838
Примечания : Cited References: 41. - We are grateful to Professor Yu. L. Raikher for useful discussions and M. A. Kazakova for the help in sample preparationThis work was supported by Russian Federal Agency of Scientific Organizations (Project No. V.44.1.15) and scientific and educational center of energy-efficient catalysis of NSU
Предметные рубрики: FERROMAGNETIC-RESONANCE
OXIDE NANOPARTICLES
WAVE ABSORBER
IRON
TRANSITION
TEMPERATURE
PARTICLES
PHASE
FNANOWIRES
FIELD
Аннотация: We report the results of comparative analysis of magnetic properties of the systems based on ε-Fe2O3, nanoparticles with different average sizes (from ∼3 to 9 nm) and dispersions. The experimental data for nanoparticles higher than 6-8 nm in size are consistent with the available data, specifically, the transition to the magnetically ordered state occurs at a temperature of ∼500 K and the anomalies of magnetic properties observed in the range of 80-150 K correspond to the magnetic transition. At the same time, Mossbauer and ferromagnetic resonance spectroscopy data as well as the results of static magnetic measurements show that at room temperature all the investigated samples contain ε-Fe2O3 particles that exhibit the superparamagnetic behavior. It was established that the magnetic properties of nanoparticles significantly change with a decrease in their size to ∼6 nm. According to high-resolution electron microscopy and Mossbauer spectroscopy data, the particle structure can be attributed to the ε-modification of trivalent iron oxide; meanwhile, the temperature of the magnetic order onset in these particles is increased, the well-known magnetic transition in the range of 80-150 K does not occur, the crystallographic magnetic anisotropy constant is significantly reduced, and the surface magnetic anisotropy plays a decisive role. This is apparently due to redistribution of cations over crystallographic positions with decreasing particle size, which was established using Mössbauer spectra. As the particle size is decreased and the fraction of surface atoms is increased, the contribution of an additional magnetic subsystem formed in a shell of particles smaller than ∼4 nm becomes significant, which manifests itself in the static magnetic measurements as paramagnetic contribution. © 2015 AIP Publishing LLC.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sofronova S. N., Gerasimova Y. V., Vtyurin A. N., Gudim, I. A., Shestakov N. P., Ivanenko A. A.
Заглавие : Infrared absorption spectrum of HoFe3(BO3)4 crystal
Коллективы : RFBR [13-02-00825, 13-02-98041, SS-4828.2012.2]
Место публикации : Vib. Spectrosc.: Elsevier Science, 2014. - Vol. 72. - P.20-25. - ISSN 0924-2031, DOI 10.1016/j.vibspec.2014.02.005. - ISSN 1873-3697
Примечания : Cited References: 18. - The work was partially supported by the RFBR through Grants No. 13-02-00825 and 13-02-98041, SS-4828.2012.2.
Предметные рубрики: MAGNETOELASTIC INTERACTIONS
IRON
GDFE3(BO3)4
Ключевые слова (''Своб.индексиров.''): holmium ferroborate--infrared absorption
Аннотация: Infrared (IR) absorption spectra of HoFe3(BO3)4 crystal have been obtained in spectral range 30–7000 cm−1 at temperatures from 4 to 423 K. Vibrational frequencies have been simulated with ‘Lady’ software package both for high-temperature and low-temperature phases. The experimental spectra have been analyzed on the basis of calculated data, and interpreted within the framework of internal vibrations of ionic complexes of HoFe3(BO3)4 crystal lattice. The spectral range under study was observed to have no Davydov splitting of internal vibrational modes due to unit cell multiplication. No effects of magnetic ordering on the IR spectra of the crystal under study were observed in the low-temperature range.
Смотреть статью,
Scopus,
WOS,
Читать в сети ИФ
Найти похожие

19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Korshunov M. M., Efremov D. V., Golubov A. A., Dolgov O. V.
Заглавие : Unexpected impact of magnetic disorder on multiband superconductivity
Коллективы : Dynasty Foundation; ICFPM; Ministry of Education and Science of the Russian Federation [14Y26.31.0007]; RFBR [12-02-31534, 13-02-01395]; Leading Scientific Schools of the Russian Federation [NSh-2886.2014.2]; DFG [1458]; EU-Japan
Место публикации : Phys. Rev. B: American Physical Society, 2014. - Vol. 90, Is. 13. - ISSN 1098-0121, DOI 10.1103/PhysRevB.90.134517. - ISSN 1550-235X
Примечания : Cited References: 41. - The authors are grateful to S.-L. Drechsler, P.J. Hirschfeld, K. Kikoin, and S.G. Ovchinnikov for useful discussions. We acknowledge partial support by the Dynasty Foundation and ICFPM (MMK), the Ministry of Education and Science of the Russian Federation (Grant No. 14Y26.31.0007), RFBR (Grant Nos. 12-02-31534 and 13-02-01395), President Grant for Government Support of the Leading Scientific Schools of the Russian Federation (NSh-2886.2014.2), DFG Priority Program 1458, and FP7 EU-Japan program IRON SEA.
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTIVITY
PARAMAGNETIC IMPURITIES
IRON
CONDUCTIVITY
ALLOYS
Аннотация: We analyze how the magnetic disorder affects the properties of the two-band s± and s++ models, which are the subject of discussions regarding iron-based superconductors and other multiband systems like MgB2. We show that there are several cases when the transition temperature Tc is not fully suppressed by magnetic impurities in contrast to the Abrikosov-Gor'kov theory, but a saturation of Tc takes place in the regime of strong disorder. These cases are: (1) the purely interband impurity scattering and (2) the unitary scattering limit. We show that in the former case the s± gap is preserved, while the s++ state transforms into the s± state with increasing magnetic disorder. For case (2), the gap structure remains intact.
Смотреть статью,
Scopus,
WoS,
WOS,
Читать в сети ИФ
Найти похожие

20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Maiti S., Korshunov M. M., Chubukov A.V.
Заглавие : Gap symmetry in KFe2As2 and the cos 4θ gap component in LiFeAs
Место публикации : Phys. Rev. B: American Physical Society, 2012. - Vol. 85, Is. 1. - Ст.14511. - ISSN 1098-0121, DOI 10.1103/PhysRevB.85.014511
Примечания : Cited References: 49. - We are thankful to S. Borisenko, S. Davis, R. Fernandes, P. Hirschfeld, I. Eremin, D. Evtushinsky, A. Kordyuk, K. Kuroki, Y. Matsuda, A. Rost, M. Vavilov, and V. Zabolotnyy for useful discussions. This work was supported by NSF-DMR-0906953 (SM and AVC) and by the Humboldt Foundation (AVC). MMK is grateful for support from RFBR (Grant No. 09-02-00127), the Presidium of RAS program N5.7, the FCP Scientific and Research and Educational Personnel of Innovative Russia for 2009-2013 (GK P891 and GK16.740.12.0731), and the President of Russia (Grant No. MK-1683.2010.2).
Предметные рубрики: SUPERCONDUCTING GAPS
IRON
Аннотация: We revisit the issue of the gap symmetry in KFe2As2, which is an Fe pnictide superconductor with only hole pockets. Previous theoretical studies mostly argued for a d−wave gap in KFe2As2 since transport and thermodynamic measurements point to the presence of the gap nodes. However, a d-wave gap is inconsistent with recent laser-based angle-resolved photoemission measurements. We propose a scenario for a nodal s−wave superconductivity induced by a nonmagnetic intraband and interband interactions between fermions near hole pockets. The superconducting gap changes sign between the hole pockets and has cos4θ angular dependence and accidental nodes on one or several hole pockets. We argue that strong angle dependence is the consequence of near-degeneracy between interpocket and intrapocket interaction on the hole pockets. We also analyze the cos4θ angular dependence of the gap in other Fe pnictides and compare theoretical results with the photoemission experiments of LiFeAs.
Смотреть статью,
Scopus,
WoS,
Читать в сети ИФ
Найти похожие