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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tarasov A. S., Visotin M. A., Varnakov S. N., Ovchinnikov S. G.
Заглавие : Growth of α-FeSi2 nanocrystals on silicon surface: the impact of gold and the Si/Fe flux ratio, the origin and the prediction of α/Si orientation relationships and interface structures
Коллективы : International Online Workshop on the properties of Functional MAX-materials, Институт физики им. Л.В. Киренского Сибирского отделения РАН
Место публикации : 1st FunMAX Workshop 2020: Book of Abstracts/ , Ин-т физики им. Л.В. Киренского. - 2020. - P11
Примечания : Cited References: 2. - The study was carried out with the financial support of the Government of the Russian Federation within the framework of a grant for the creation of world-class laboratories (Agreement No. 075-15-2019-1886).
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balatskiy D. V., Kraynova G. S., Plotnikov V. S., Ilin N. V., Tkachev V. V., Knyazev Yu. V.
Заглавие : Magnetic Properties of Fe–Cu–Nb–Si–B Spinning Ribbons
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2020. - Vol. 84, Is. 9. - P.1126-1130. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873820090063
Примечания : Cited References: 7
Аннотация: Dependences of relative saturation magnetization on temperature are measured for amorphous nanocrystalline ribbons of Finemet-type FeCu1Nb3Si13.5B8, FeCu1Nb3Si13B6, and FeCu1Nb3Si13B13 compositions. The character of the structural relaxation of amorphous alloys is established by means of Mossbauer spectroscopy, and the main magnetic characteristics are determined. It is found that the structural relaxation of amorphous ribbon proceeds in several stages upon annealing.
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Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Denisova E. A., Nemtsev I. V., Telegin S. V., Iskhakov R. S., Kuzovnikova L. A., Shepeta N. A.
Заглавие : Microstructure and magnetic properties of Co58Ni10Fe5B16Si11 and Co58Ni10Fe5B16Si11-Al2O3 bulk amorphous coatings prepared by plasma spraying
Коллективы : International Conference on High-Tech and Innovations in Research and Manufacturing
Место публикации : J. Phys.: Conf. Ser. - 2020. - Vol. 1582, Is. 1. - Ст.012078. - DOI 10.1088/1742-6596/1582/1/012078
Примечания : Cited References: 18. - This work was funded by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, the Krasnoyarsk Regional Fund for the Support of Scientific and Technical Activities (project no. 18-42-240006 Nanomaterials with magnetic properties determined by the topological features of the nanostructure). The authors thank the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS” for the provided equipment
Аннотация: The bulk soft magnetic glassy Co58Ni10Fe5B16Si11 alloy specimens have been prepared by plasma spray deposition. In order to increase resistivity of the material, the bulk Co58Ni10Fe5B16Si11-Al2O3 composite materials were fabricated. The investigations of structure and magnetic properties of the bulk samples were carried out by X-ray diffraction, electron microscopy and magnetic measurements. The relation of the structural features and magnetic characteristics of the bulk coating to the main parameters of the deposition regimes was determined. Optimized plasma spray deposition parameters allowed obtaining bulk glassy samples with magnetic parameters that are not inferior to the characteristics of a thermally treated rapidly quenched ribbon with the same composition. It was found that the bulk amorphous coatings can be characterized as a heterophase system. The relaxation annealing of the Co58Ni10Fe5B16Si11 bulk coating leads to a phase transition in this alloy in the precrystallization temperature range. The magnetic properties of the both kinds of coatings are correlated with changes in the microstructure. The appearance of nanocrystalline phase with TC640 K during relaxation heat treatment leads to a decrease of the coercivity and to an increase of the permeability. A comparison between the magnetic properties of the CoNiFe-BSi coating and (CoNiFe-BSi)-Al2O3, composite coating is carried out.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Tarasov I. A., Smolyarova T. E., Yakovlev I. A., Nemtsev I. V., Varnakov S. N., Ovchinnikov S. G.
Заглавие : Modification of optical and magneto-optical response of highly textured Au3Fe1-x/Fe Janus-like nanocrystals grown on amorphous silicon dioxide surface
Коллективы : International workshop on functional MAX-materials, Kirensky Institute of Physics
Место публикации : International workshop on functional MAX-materials (1st FunMax). - 2020. - P.22
Примечания : The study was carried out with the financial support of the Government of the Russian Federation within the framework of a grant for the creation of world-class laboratories (Agreement No. 075-15-2019-1886)
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Tarasov I. A., Visotin M. A., Varnakov S. N., Ovchinnikov S. G., Farle M.
Заглавие : Growth of α-FeSi2 nanocrystals on silicon surface: the impact of gold and the Si/Fe flux ratio, the origin and the prediction of α/Si orientation relationships and interface structures
Коллективы : International workshop on functional MAX-materials, Kirensky Institute of Physics
Место публикации : International workshop on functional MAX-materials (1st FunMax). - 2020. - P.11
Примечания : Cited references: 2. - The study was carried out with the financial support of the Government of the Russian Federation within the framework of a grant for the creation of world-class laboratories (Agreement No. 075-15-2019-1886)
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tarasov I. A., Smolyarova T. E., Yakovlev I. A., Nemtsev I. V., Varnakov S. N., Varnakov S. N., Ovchinnikov S. G.
Заглавие : Modification of optical and magneto-optical response of highly textured Au3Fe1-x/Fe Janus-like nanocrystals grown on amorphous silicon dioxide surface
Коллективы : International Online Workshop on the properties of Functional MAX-materials, Kirensky Institute of Physics, Институт физики им. Л.В. Киренского Сибирского отделения РАН
Место публикации : 1st FunMAX Workshop 2020: Book of Abstracts. - 2020. - P22
Примечания : The study was carried out with the financial support of the Government of the Russian Federation within the framework of a grant for the creation of world-class laboratories (Agreement No. 075-15-2019-1886).
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivantsov R. D., Ivanova O. S., Zharkov S. M., Molokeev M. S., Krylov A. S., Gudim I. A., Edelman I. S.
Заглавие : Magnetic circular dichroism in the canted antiferromagnet α-Fe2O3: bulk single crystal and nanocrystals
Место публикации : J. Magn. Magn. Mater. - 2020. - Vol. 498. - Ст.166208. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2019.166208. - ISSN 1873-4766 (eISSN)
Примечания : Cited References: 60. - The authors thank S.L. Sukhachev for help in conducting absorption experiments and S.G. Ovchinnikov for fruitful discussions. The work is supported by Russian Academy of Sciences in the frame of the Project № 0356-2017-0030.
Аннотация: Hematite, α-Fe2O3, is a canted antiferromagnet with the Neel temperature of 960 K. The Morin transition, which occurs when the temperature is lowered to ∼260 K, when the magnetic moments of the sublattices become strictly antiparallel to each other and the resulting magnetic moment disappears, is a characteristic feature of this compound. Detailed investigations are presented here of the magneto-optical effects in the α-Fe2O3 nanoparticles in the transmitted light and in the α-Fe2O3 single crystal in the reflected light. Two types of magneto-optic features were revealed in the magnetic circular dichroism (MCD) spectrum. Some of them described by the Gauss line shape were associated with one-ion d-d transitions. Others were described by the S-shaped line with the inflection points corresponding to the absorption maxima. Last features were assigned to the pair exciton-magnon transitions. An exceptionally strong S-shaped line at 2.0-2.5 eV appeared to be a unique feature of α-Fe2O3 distinguishing it from other iron oxide compounds. The origin of the high effectiveness of the pair exciton-magnon interaction giving rise to this strong S-shaped feature in the MCD spectrum of α-Fe2O3 is discussed.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Komogortsev S. V., Chekanova L. A., Yaroslavtsev R. N., Bayukov O. A., Velikanov D. A., Volochaev M. N., Cheremiskina E. V., Bairmani M. S., Eroshenko P. E., Iskhakov R. S.
Заглавие : Magnetite Nanocrystals with a High Magnetic Anisotropy Constant due to the Particle Shape
Место публикации : Tech. Phys. Lett. - 2019. - Vol. 45, Is. 9. - P.878-881. - ISSN 10637850 (ISSN), DOI 10.1134/S1063785019090116
Примечания : Cited References: 20. - This study was supported in part by the Russian Foundation for Basic Research, Government of Krasnoyarsk Krai, Science Foundation of Krasnoyarsk Krai within research projects nos. 18-42-240006 (“Nanomaterials with Magnetic Properties Determined by the Nanostructure Topological Features”) and 18-43-243003 (“Sonochemical Treatment of Magnetic Nanoparticles As a Way of Modifying Their Properties”) and a special program of the Ministry of Education and Science of the Russian Federation for Siberian Federal University.
Аннотация: Chemical solution deposition in the presence of arabinogalactan makes it possible to prepare magnetite nanocrystals in the form of square plates with a high aspect ratio (~1/9). The magnetic anisotropy constant of particles is several times higher than that of spherical magnetite particles, which enhances the hysteretic properties with a small particle volume retained.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou, Guojun, Jia, Xiaofang, Guo, Shaoqiang, Molokeev M. S., Zhang, Junying, Xia, Zhiguo
Заглавие : Role of Halogen Atoms on High-Efficiency Mn2+ Emission in Two-Dimensional Hybrid Perovskites
Место публикации : J. Phys. Chem. Lett. - 2019. - Vol. 10, Is. 16. - P.4706-4712. - ISSN 1948-7185, DOI 10.1021/acs.jpclett.9b01996
Примечания : Cited References: 37. - This work is supported by the National Natural Science Foundation of China (No. 51722202 and 51572023), the Natural Science Foundations of Beijing (2172036), the Fundamental Research Funds for the Central Universities (FRF-TP-18-002C1), and the Guangdong Provincial Science & Technology Project (No. 2018A050506004).
Предметные рубрики: ENERGY-TRANSFER
LIGHT-EMISSION
DOPING MN2+
LEAD-FREE
NANOCRYSTALS
Аннотация: Doped halide pervoskites as highly efficient light emitters have recently fascinated the research community, while the influence of halogen atoms X (X = Cl, Br, I) on the hybrid energy levels and photoluminescence properties remains a challenge. Here, the role of X compositions in the two-dimensional hybrid perovskite BA2PbX4 (BA = C4H9NH3) on the doped Mn2+ emission is identified, wherein Mn2+ reveals a strong luminescence dependence on the nature of the halogen, and optimum Mn2+ emission with a record quantum yield of 60.1% has been achieved in BA2PbBr4. Density functional theory calculations show that BA2PbBr4 holds low Br vacancy concentration and unique coupled states of the Mn-3d level and Pb-6p level at the conduction band minimum, leading to efficient energy transfer from the host to Mn2+. Our work sheds new light on the methods to realize strong exciton–dopant exchange coupling for achieving high-efficiency dopant luminescence.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Liu, Ying, Rong, Ximing, Li, Mingze, Molokeev M. S., Zhao, Jing, Xia, Zhiguo
Заглавие : Incorporating rare-earth terbium(III) ions into Cs2AgInCl6:Bi nanocrystals toward tunable photoluminescence
Место публикации : Angew. Chem. - 2020. - Vol. 132, Is. 28. - P.11731-11737. - ISSN 1521-3757(eISSN), DOI 10.1002/ange.202004562
Примечания : Cited References: 43
Предметные рубрики: HALIDE DOUBLE PEROVSKITE
LEAD-FREE
LANTHANIDE
STABILITY
EMISSION
Аннотация: The incorporation of impurity ions or doping is a promising method for controlling the electronic and optical properties and the structural stability of halide perovskite nanocrystals (NCs). Herein, we establish relationships between rare‐earth ions doping and intrinsic emission of lead‐free double perovskite Cs2AgInCl6 NCs to impart and tune the optical performances in the visible light region. Tb3+ ions were incorporated into Cs2AgInCl6 NCs and occupied In3+ sites as verified by both crystallographic analyses and first‐principles calculations. Trace amounts of Bi doping endowed the characteristic emission (5D4→7F6‐3) of Tb3+ ions with a new excitation peak at 368 nm rather than the single characteristic excitation at 290 nm of Tb3+. By controlling Tb3+ ions concentration, the emission colors of Bi‐doped Cs2Ag(In1−xTbx)Cl6 NCs could be continuously tuned from green to orange, through the efficient energy‐transfer channel from self‐trapped excitons to Tb3+ ions. Our study provides the salient features of the material design of lead‐free perovskite NCs and to expand their luminescence applications.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tarasov I. A., Smolyarova T. E., Nemtsev I. V., Yakovlev I. A., Volochaev M. N., Solovyov L. A., Varnakov S. N., Ovchinnikov S. G.
Заглавие : Tailoring the preferable orientation relationship and shape of α-FeSi2nanocrystals on Si(001): The impact of gold and the Si/Fe flux ratio, and the origin of α/Si boundaries
Место публикации : CrystEngComm. - 2020. - Vol. 22, Is. 23. - P.3943-3955. - ISSN 14668033 (ISSN), DOI 10.1039/d0ce00399a
Примечания : Cited References: 52. - The experimental part of the reported study was funded by the Russian Science Foundation, project no. 16-13-00060-Π. Theoretical analysis of the ORs of the α-FeSi2 nanocrystals grown was supported by the Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science via research project No. 18-42-243013. We also acknowledge the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS” for support with carrying out the microscopic investigations. I. A. Tarasov personally thanks M. A. Visotin for continuous fruitful discussion about the energetics of the formation of the α-FeSi2 nanocrystals
Аннотация: The growth of α-FeSi2 nanocrystal ensembles on gold-activated and gold-free Si(001) surfaces at different Si/Fe flux ratios via molecular beam epitaxy is reported. The study reveals that the utilisation of gold as a catalyst regulates the preferable orientation relationship (OR) of the nanocrystals to silicon and their morphology at a given Si/Fe flux ratio. α-FeSi2 free-standing crystals with continuously tuned sizes from 30 nm up to several micrometres can be grown with an α(001)//Si(001) basic OR under gold-assisted conditions and an α(111)//Si(001) OR under gold-free growth conditions on a Si(001) surface. The preferred morphology of nanocrystals with a particular OR can be altered through changes to the Si/Fe flux ratio. Herein, the microstructure and basic OR between the silicide nanocrystals and the silicon substrate, and the formation of nanocrystal facets were analysed in detail with the help of microscopic techniques and simulation methods based on the analysis of near coincidence site (NCS) distributions at silicide/silicon interfaces. On the basis of the simulations used, we managed to reveal the nature of the interfaces observed for the main types of α-FeSi2 nanocrystals grown. Three types of interfaces typical for nanoplates with an α(001)//Si(001) basic OR, which are (i) stepped, (ii) stressed, and (iii) flat, are explained based on the tendency for the NCS density to increase at the interface. The results presented reveal the potential for the bottom-up fabrication of α-FeSi2 nanocrystals with tuned physical properties as potentially important contact materials and as building blocks for future nanoelectronic devices.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Liu, Ying, Rong, Ximing, Li, Mingze, Molokeev M. S., Zhao, Jing, Xia, Zhiguo
Заглавие : Incorporating rare-earth terbium(III) Ions into Cs2AgInCl6:Bi nanocrystals toward tunable photoluminescence
Место публикации : Angew. Chem. - Int. Edit. - 2020. - Vol. 59, Is. 28. - P.11634-11640. - ISSN 1433-7851, DOI 10.1002/anie.202004562. - ISSN 1521-3773(eISSN)
Примечания : Cited References: 43. - This work is supported by the National Natural Science Foundation of China (51961145101, 51972118 and 51722202), Fundamental Research Funds for the Central Universities (FRFTP-18-002C1), Guangdong Provincial Science & Technology Project (2018A050506004) and the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137). This work is also funded by RFBR according to the research project No. 19-52-80003.
Предметные рубрики: HALIDE DOUBLE PEROVSKITE
LEAD-FREE
LANTHANIDE
STABILITY
EMISSION
Аннотация: The incorporation of impurity ions or doping is a promising method for controlling the electronic and optical properties and the structural stability of halide perovskite nanocrystals (NCs). Herein, we establish relationships between rare‐earth ions doping and intrinsic emission of lead‐free double perovskite Cs2AgInCl6 NCs to impart and tune the optical performances in the visible light region. Tb3+ ions were incorporated into Cs2AgInCl6 NCs and occupied In3+ sites as verified by both crystallographic analyses and first‐principles calculations. Trace amounts of Bi doping endowed the characteristic emission (5D4→7F6‐3) of Tb3+ ions with a new excitation peak at 368 nm rather than the single characteristic excitation at 290 nm of Tb3+. By controlling Tb3+ ions concentration, the emission colors of Bi‐doped Cs2Ag(In1−x Tbx )Cl6 NCs could be continuously tuned from green to orange, through the efficient energy‐transfer channel from self‐trapped excitons to Tb3+ ions. Our study provides the salient features of the material design of lead‐free perovskite NCs and to expand their luminescence applications.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xiao, Hui, Dang, Peipei, Yun, Xiaohan, Li, Guogang, Wei, Y.i., Xiao, Xiao, Zhao, Yajie, Molokeev M. S., Cheng, Ziyong, Lin, Jun
Заглавие : Solvatochromic Photoluminescent Effects in All-Inorganic Manganese(II)-Based Perovskites by Highly Selective Solvent-Induced Crystal-to-Crystal Phase Transformations
Место публикации : Angew. Chem. Int. Edit. - 2021. - Vol. 60, Is. 7. - P.3699-3707. - ISSN 1433-7851, DOI 10.1002/anie.202012383. - ISSN 1521-3773(eISSN)
Примечания : Cited References: 85. - This work was supported by National Natural Science Foundation of China (NSFC 51932009, 51772288, 52072349, 51672259) and the Joint Fund Project to Promote Science and Technology Cooperation Across the Taiwan Straits (U2005212), the Science and Technology Cooperation Fund between Chinese and Australian Governments (2017YFE0132300), CAS-Croucher Funding Scheme for Joint Laboratories (CAS18204), Chinese Academy of Sciences (YZDY-SSWJSC018)
Предметные рубрики: LEAD-FREE
HALIDE PEROVSKITE
NANOCRYSTALS
MN2+
LUMINESCENCE
Аннотация: The development of lead‐free perovskite photoelectric materials has been an extensive focus in the recent years. Herein, a novel one‐dimensional (1D) lead‐free CsMnCl3(H2O)2 single crystal is reported with solvatochromic photoluminescence properties. Interestingly, after contact with N,N‐dimethylacetamide (DMAC) or N,N‐dimethylformamide (DMF), the crystal structure can transform from 1D CsMnCl3(H2O)2 to 0D Cs3MnCl5 and finally transform into 0D Cs2MnCl4(H2O)2. The solvent‐induced crystal‐to‐crystal phase transformations are accompanied by loss and regaining of water of crystallization, leading to the change of the coordination number of Mn2+. Correspondingly, the luminescence changes from red to bright green and finally back to red emission. By fabricating a test‐paper containing CsMnCl3(H2O)2, DMAC and DMF can be detected quickly with a response time of less than one minute. These results can expand potential applications for low‐dimensional lead‐free perovskites.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Эдельман, Ирина Самсоновна, Иванова, ОксанаС таниславовна, Заблуда, Владимир Николаевич, Иванцов, Руслан Дмитриевич, Бондаренко, Геннадий Васильевич, Зайковский В. И., Степанов С. А.
Заглавие : Формирование магнитных нанокристаллов в Ge-стеклах, допированных Fe и Dy
Место публикации : Российские нанотехнологии. - Москва: Парк-медиа, 2008. - Т. 3, № 11-12. - С. 136-142. - ISSN 1992-7223. - ISSN 1993-4068(eissn)
ГРНТИ : 29.19
УДК : 537.632; 538.911; 538.955; 537.621
Предметные рубрики:
Аннотация: Синтезированы магнитные нанокомпозиты на основе германатных стекол, допированных оксидами Fe и Dy в невысоких концентрациях. С помощью электронной микроскопии высокого разрешения выявлено формирование наночастиц размерами от ~5 до 20 нм в стеклах, подвергнутых термообработкам в различных режимах. Наночастицы имели хорошо разрешимую кристаллическую структуру. С помощью микрозондового флуоресцентного рентгеновского анализа показано, что железо и диспрозий сосредоточены в частицах. Полевые зависимости магнитооптических эффектов свидетельствуют о магнитном порядке в частицах. Сравнение межплоскостных расстояний, полученных с помощью электронной микродифракции, с известными оксидными соединениями железа не дало однозначных результатов. В тоже время почти все особенности спектров магнитного кругового дихроизма в стеклах соответствуют аналогичным особенностям, наблюдавшимся ранее в ферритах-гранатах, что позволило предположить формирование частиц с искаженной структурой граната.Magnetic nanocomposites were synthesized on the base of germanate glasses doped with low concentrations of iron and dysprosium oxides. Formation of nanoparticles of 5-20 nm in size in the glasses subjected to the additional thermal treatment was proved with High Resolution Transmitted Electron Microscope. Nanoparticles had well resolved crystal structure. Fe and Dy were shown to be collected inside nanoparticles. Dependences of magneto-optical effects on the external magnetic field showed the existence of magnetic order in particles. Comparison of inter planar crystal spacing obtained with that of the known Fe oxide compounds gave no unambiguous results. At the same time almost all peculiarities observed in the magnetic circular dichroism spectra of the glasses corresponded to that in Fe-garnets what allowed supposing formation of the particles with the distorted garnet structure.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Павлов А. В., Квеглис, Людмила Иосифовна, Джес А. В., Сапрыкин Д. Н., Насибуллин Р. Т., Великанов, Дмитрий Анатольевич, Немцев, Иван Васильевич, Шалаев П. О.
Заглавие : Магнетизм бериллиевой керамики со структурой перовскита BeTiO3
Место публикации : Фундамент. пробл. совр. материаловед. - 2022. - Т. 19, № 1. - С. 115-124. - ISSN 1811-1416, DOI 10.25712/ASTU.1811-1416.2022.01.013; Basic Probl. Mater. Sci.
Примечания : Библиогр.: 24
Аннотация: Известно, что введение в ВеО-керамику добавки TiO2 после термообработки в восстановительной атмосфере сопровождается значительным увеличением электропроводности и способностью поглощать электромагнитное излучение в широком диапазоне частот. До сих пор механизм этого влияния до конца не установлен. С использованием методов Лоренцевой электронной микроскопии в сканирующем электронном микроскопе, а также вибрационного магнитометра, установлено проявление ферромагнетизма. Такая особенность бериллиевой керамики способствует поглощению электромагнитной энергии в объемных образцах, содержащих наночастицы TiO2. Установлено, что присутствие наночастиц способствует формированию структуры перовскита в зонах спекания BeO + TiO2. В структуре перовскита возможна поляризация молекул за счет формирования поляронов, что приводят к деформации решетки и смещению атомов. В результате такого смещения происходит изменение ближнего порядка в структуре перовскита и к образованию икосаэдрической фазы из исходной фазы со структурой кубоктаэдра. Малый размер атома бериллия позволяет организоваться тетраэдрической плотной упаковке в форме икосаэдра из атомов кислорода вокруг центрального атома бериллия. В результате повышается атомная плотность и плотность электронных состояний на уровне Ферми. Предлагаются модели для объяснения причины появления ферромагнетизма и электропроводности, которые обнаружены в бериллиевой керамике. С помощью метода спин-поляризованных электронов проведены расчеты электронной структуры нанокластеров с различным ближним порядком.It is known that the introduction of TiO2 additives into BeO ceramics after heat treatment in a reducing atmosphere is accompanied by a significant increase in electrical conductivity and the ability to absorb electromagnetic radiation in a wide frequency range. Until now, the mechanism of this influence has not been fully established. Using the methods of Lorentzian electron microscopy in a scanning electron microscope, as well as a vibration magnetometer, the manifestation of ferromagnetism was established. This feature of beryllium ceramics promotes the absorption of electromagnetic energy in bulk samples containing TiO2 nanoparticles. It was found that the presence of nanoparticles promotes the formation of the perovskite structure in the BeO + TiO2 sintering zones. In the structure of perovskite, polarization of molecules is possible due to the formation of polarons, which leads to deformation of the lattice and displacement of atoms. As a result of this displacement, a change in the short-range order in the perovskite structure occurs and to the formation of an icosahedral phase from the initial phase with a cuboctahedral structure. The small size of the beryllium atom makes it possible to organize a tetrahedral close packing in the form of an icosahedron of oxygen atoms around the central beryllium atom. As a result, the atomic density and the density of electronic states at the Fermi level increase. Models are proposed to explain the reasons for the appearance of ferromagnetism and electrical conductivity found in beryllium ceramics. Using the spin-polarized electron method, the electronic structure of nanoclusters with different short-range orders has been calculated.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Avramov P. V., Kuzubov A. A., Fedorov D. G., Irle S., Morokuma K.
Заглавие : Strong Electron Correlations Determine Energetic Stability and Electronic Properties of Er-Doped Goldberg-Type Silicon Quantum Dots
Место публикации : J. Phys. Chem. C. - 2009. - Vol. 113, Is. 36. - P.15964-15968. - SEP 10. - ISSN 1932-7447, DOI 10.1021/jp904996e
Примечания : Cited Reference Count: 43. - Гранты: This work was supported by a CREST (Core Research for Evolutional Science and Technology) grant in the Area of High Performance Computing for Multiscale and Multiphysics Phenomena from the Japan Science and Tcchnology Agency (JST) and a collaborative RFBR-JSPS Grant 0902-92107-Phi. One of the authors (S.I.) also acknowledges support by the Program for Improvement of Research Environment for Young Researchers from Special Coordination Funds for Promoting Science and Technology (SCF) commissioned by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan.Финансирующая организация: Japan Science and Tcchnology Agency (JST); RFBR-JSPS Grant; Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan
Предметные рубрики: IMPLANTED POROUS SILICON
AUGMENTED-WAVE METHOD
MU M LUMINESCENCE
SI NANOCRYSTALS
THIN-FILMS
BASIS-SET
ERBIUM
PHOTOLUMINESCENCE
DENSITY
PSEUDOPOTENTIALS
Ключевые слова (''Своб.индексиров.''): ab initio--atomic structure--density functionals--empirical pseudo-potential--endohedrals--energetic stability--er-doped--erbium complexes--erbium ion--experimental data--hartree-fock--many body perturbation theory--mass centers--perturbation approach--plane wave--pseudopotentials--quantum dot--silicon quantum dots--strong binding--strong electron correlations--theoretical result--crystal atomic structure--electron correlations--electron density measurement--electronic properties--electronic structure--erbium--perturbation techniques--structural optimization--semiconductor quantum dots
Аннотация: Atomic and electronic structures of Goldberg-type silicon quantum dots and their endohedral erbium complexes were studied using ab initio and plane wave pseudopotential density functional and Moller-Plesset many-body perturbation theories. During atomic structure optimizations, the erbium ions occupy mass centers inside the central hollows of quantum dots of different symmetries. It was found that strong electron correlations within the Er 4f shell taken into account by empirical pseudopotential and post-Hartree-Fock perturbation approaches are responsible for strong binding of Er ions to quantum dots. We elucidate the effects of symmetry and discuss theoretical results in comparison to available experimental data,
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivanova O. S., Edelman I. S., Ovchinnikov S. G., Thakur A., Thakur P., Sukhachev A. L., Knyazev Yu. V., Ivantsov R. D., Molokeev M. S.
Заглавие : Effect of cobalt concentration on the magnetic properties of the Co1–xMgxFe2O4 nanocrystals
Колич.характеристики :7 с
Место публикации : JETP Lett. - 2024. - Vol. 119, Is. 2. - P.104-110. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364023603457. - ISSN 10906487 (eISSN)
Примечания : Cited References: 26. - The research was carried out at the expense of the Russian Science Foundation Grant # 23-22-10025, https://rscf.ru/project/23-22-10025/, Krasnoyarsk Regional Science Foundation
Аннотация: Nanoparticles of Co1–xMgxFe2O4 with x equal to 0, 0.2, 0.4, 0.6, 0.8 and 1.0 have been synthesized. For all values of x, they are nanocrystals with a cobalt ferrite structure and an average linear size (56 ± 3) nm. Based on the analysis of the Mossbauer effect spectra, the Co2+ ions were shown to occupy only octahedral positions at all values of x. The experimentally obtained dependence of the nanoparticles magnetization on x corresponds to the dependence calculated using the Mossbauer effect data, except for the sample with x = 1.0. The effective magnetic anisotropy constant estimated for 0 K from the analysis of the coercive force temperature dependences decreases from 5.27 × 106 at x = 0 to 1.29 × 106 erg/cm3 at x = 0.8 and drops sharply to 4 × 104 erg/cm3 at x = 1.0
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shapovalov V. V., Shapovalov V. A., Sluzhbin Yu. A., Drokina T. V., Vorotynov A. M., Valkov V. I.
Заглавие : Characteristics of nanocomplexes with iron Fe3+ in Glass Ionomer Cement powder by ESR method
Место публикации : Phys. Solid State. - 2023. - Vol. 65, Is. 2. - P.296-298. - ISSN 10637834 (ISSN), DOI 10.21883/PSS.2023.02.55415.489. - ISSN 10906460 (eISSN)
Примечания : Cited References: 13
Аннотация: The study is part of nanomedical biotechnology and is carried out by probing these systems using the Electronic Spin Resonance (ESR) method. The paper investigates Glass Ionomer Cement powder widely used in dental practice Glass Ionomer Cement C-Plus Triplekit-TM. To assess the quality of Glass Ionomer Cement and use ESR radiospectroscopy in the range from low (T=4.2 K) to room (T=300 K) temperatures. A new characteristic of compounds with nanocomplexes of magnetic iron ions Fe3+ is applied.
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19.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Ignatchenko V. A., Mankov Yu. I.
Заглавие : Effects of inhomogeneities with extended correlations on the spin wave spectrum in nanocrystals and superlattices
Коллективы : Moscow International Symposium on Magnetism, Московский государственный университет им. М.В. Ломоносова, Российский фонд фундаментальных исследований
Место публикации : Moscow Int. Symp. on Magnet. (MISM-2008): June 20-25, 2008, Moscow : book of abstract. - 2008. - Ст.24TL-F-3. - p.581-582
Примечания : These works were supported by the Grant of the RF President, SS-3818.2008.3.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou, Guojun, Ding, Jialiang, Jiang, Xingxing, Zhang, Jian, Molokeev M. S., Ren, Qiqiong, Zhou, Jun, Li, Shili, Zhang, Xian-Ming
Заглавие : Coordination units of Mn2+ modulation toward tunable emission in zero-dimensional bromides for white light-emitting diodes
Место публикации : J. Mater. Chem. C. - 2022. - Vol. 10, Is. 6. - P.2095-2102. - ISSN 2050-7526, DOI 10.1039/d1tc05680h. - ISSN 2050-7534(eISSN)
Примечания : Cited References: 57. - The present work was supported by the Natural Science Foundation of China (21871167), the 1331 Project of Shanxi Province and the Postgraduate Innovation Project of Shanxi Normal University (2019XBY018), the Beijing Natural Science Foundation (No. 2214068) and funded by RFBR according to the research project no. 19-52-80003
Предметные рубрики: HALIDE PEROVSKITE NANOCRYSTALS
RECENT PROGRESS
DOPING MN2+
Аннотация: Organic–inorganic metal halides have become a multifunctional platform for manipulating photoluminescence due to highly efficient and tunable emissions, especially for lead-free Mn2+-based halides. Herein, the zero-dimensional (0D) bromides of (C5H14N3)2MnBr4 and (CH6N3)2MnBr4 with different coordination environments were designed and synthesized by a solvent evaporation method. They exhibit green and red broadband emission peaks at 528 nm and 627 nm with high photoluminescence quantum yields of 86.83% and 61.91%, respectively, which are attributed to the d–d transition (4T1(G) → 6A1(S)) of [MnBr4]2− tetrahedral and [Mn3Br12]6− octahedral units. The cases emphasize the effect of organic ligands on the intrinsic emissions of Mn2+ ions, thereby revealing the luminescence mechanism of Mn2+ ions in 0D isolated structures through the Tanabe–Sugano (TS) energy diagram. Thanks to their bright and stable emissions, the fabricated white light-emitting diode (LED) based on (C5H14N3)2MnBr4 and (CH6N3)2MnBr4 provides an outstanding color rendering index (Ra) of 90.8 at a correlated color temperature (CCT) of 3709 K, along with the CIE chromaticity coordinates of (0.3985, 0.3979) and a luminous efficacy of 51.2 lm W−1. This work aims at clarifying the relationship between the coordination units of Mn2+ and tunable emissions, and in particular, proposes a new strategy to explore phosphors excited by blue light for white LEDs.
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