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 Найдено в других БД:Каталог книг и брошюр библиотеки ИФ СО РАН (7)Каталог журналов библиотеки ИФ СО РАН (1)
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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Астахов, Александр Михайлович, Дюгаев, Константин Петрович, Кузубов, Александр Александрович, Наслузов, Владимир Александрович, Васильев, Александр Дмитриевич, Бука, Эдуард Станиславович
Заглавие : Теоретическое исследование строения нитриминов. I. структура 2-нитрогуанидина и его алкилпроизводных
Место публикации : Журнал структурной химии. - Новосибирск: Изд-во СО РАН, 2009. - Т. 50, № 2. - С. 216-226. - ISSN 0136-7463
ГРНТИ : 31.15
УДК : 544.144.2 + 544.183 + 547.495.9
Ключевые слова (''Своб.индексиров.''): энергоемкие соединения--нитримины--energetic compounds--nitrimines--nitroguanidine--molecular structure--bond lengths--bond angles--quantum-chemical calculations--нитрогуанидин--строение молекул--длины связей--валентные углы--квантово-химические расчеты
Аннотация: Молекулярная структура 2-нитрогуанидина и его 1-метил-, 1-этил- и 1,1,3,3-тетраметил-производных изучена расчетными методами квантовой химии. Полученные результаты сравниваются с рентгеноструктурными данными. Показано, что увеличение базиса выше 6-31G, использование поляризационных функций и учет электронной корреляции не улучшает приближения к экспериментальным данным. Главной причиной этого является значительное влияние кристаллического поля на молекулярные геометрические параметры.The molecular structure of 2-nitroguanidine and its 1-methyl, 1-ethyl, and 1,1,3,3-tetramethyl derivatives was studied by quantum-chemical methods. The results were compared with X-ray data. Using a basis larger than 6-31G and polarization functions and including electron correlation in calculations did not improve agreement with experiment. The major reason for this is the considerable effect of the crystal field on the geometrical parameters of the molecules.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zinenko V. I., Pavlovskii M. S.
Заглавие : Lattice dynamics of BiFeO3: The untypical behavior of the ferroelectric instability under hydrostatic pressure
Место публикации : JETP Letters. - 2008. - Vol. 87, Is. 6. - P.288-291. - ISSN 0021-3640, DOI 10.1134/S0021364008060052
Примечания : Cited References: 15
Предметные рубрики: AB-INITIO CALCULATIONS
PEROVSKITE
Аннотация: Within a nonempirical model of an ionic crystal with the inclusion of the dipole and quadrupole ion polarizations, the lattice vibrational frequencies, high-frequency dielectric constant, Born dynamic charges, and the elasticity moduli of the BiFeO3 crystal have been calculated and their dependencies on the hydrostatic pressure in the cubic, rhombic, and rhombohedral phases have been determined. The results indicate the presence of the ferroelectric instability, which depends weakly on the pressure in all of the phases investigated. The dependence of the crystal lattice dynamics on the applied pressure for the cubic phases of BiAlO3, BaTiO3, and PbTiO3 has been calculated for comparison.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhandun V. S., Draganyuk O. N.
Заглавие : The spin-state transition in ACo2O4 spinels (A = Be, Mg, Ca, Cd, Zn)
Место публикации : J. Magn. Magn. Mater. - 2022. - Vol. 552. - Ст.169206. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2022.169206
Примечания : Cited References: 51. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research projects № 19-42-240016: «Control of structural, magnetic, electronic, and optical properties by pressure and intercalation into functional compounds with a spinel structure containing 3d and 4f ions» and № 20-42-240004: “The effect of the composition, pressure, and dimension on the magnetic, electronic, optical, and elastic properties of the magnetic Mn+1AXn (M = Cr, Mn; Fe, A = Al, Ga, Si, Ge, P, In; X = C, N; n = 1-3) MAX-phases”. The calculations were performed with the computer resources of “Complex modeling and data processing research installations of mega-class” SRC “Kurchatovsky Institute” (http://ckp.urcki.ru)
Аннотация: The magnetic and electronic properties of the Co-based spinel oxides ACo2O4 (A = Be, Mg, Ca, Zn, Cd) were studied within GGA + U approach. It was found that the Co3+ ion is in a low-spin state due to the effect of the crystal field of octahedral symmetry. It is shown that Co3+ ion undergoes a spin-state transition into the high-spin state under the critical pressure of P = −10 GPa – −20 GPa. This pressure-induced spin-state transition is caused by the redistribution of electrons between the t2g- and eg-orbitals arising with increasing interatomic distances. The role of interatomic distances between Co3+ ion and its ligands is discussed. Thin-film form also favors the appearance of a high-spin state of Co3+ ion. At the same critical pressure, there is a sharp increase in the majority spin bandgap and a sharp decrease in the minority spin bandgap. These findings allow manipulating the spin state of Co3+ ions and bandgap width through the pressure or strain arising in thin films.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhandun V. S.
Заглавие : The magnetic, electronic, optical, and structural properties of the AB2O4 (A = Mn, Fe, Co; B = Al, Ga, In) spinels: Ab initio study
Место публикации : J. Magn. Magn. Mater. - 2021. - Vol. 533. - Ст.168015. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2021.168015
Примечания : Cited References: 38. - The reported study was funded by Russian Foundation for Basic Research , Government of Krasnoyarsk Territory , Krasnoyarsk Regional Fund of Science to the research project № 19-42-240016: «Control of structural, magnetic, electronic, and optical properties by pressure and intercalation into functional compounds with a spinel structure containing 3d and 4f ions» The calculations were performed with the computer resources of “Complex modeling and data processing research installations of mega-class” SRC “Kurchatovsky Institute” (http://ckp.urcki.ru)
Аннотация: The effect of cation composition on the magnetic, electronic, optical, and structural properties of the spinel oxides AB2O4 (A = Fe, Mn, Co; B = Al, Ga, In) were studied within DFT-GGA + U approximation. The spinels were considered both in the normal and inverse structure. FeB2O4 (B = Al, Ga, In) spinels have an inverse structure, whereas AB2O4 (A = Mn, Co; B = Al, Ga, In) prefer a normal structure. We find that the studied spinels are antiferromagnetic materials with the composition-dependent bandgap. The bandgap width is determined by the minimum of the conductive s-band formed by B-site cations states and can be increased by the applied pressure. The microscopic mechanisms of the relationship between composition, structural and electronic properties are analyzed. The ability to manipulate the structural, electronic, and optical properties is attributed to the different s-orbital energies and sizes of the B-site cations.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhandun V. S., Matsynin A. A.
Заглавие : The effect of the impurities on the magnetic, electronic and optical properties of Mn5Ge3
Место публикации : Chin. J. Phys. - 2020. - Vol. 68. - P.9-18. - ISSN 05779073 (ISSN), DOI 10.1016/j.cjph.2020.06.027
Примечания : Cited References: 29. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research projects № № 19-42-240016 : «Control of structural, magnetic, electronic, and optical properties by pressure and intercalation into functional compounds with a spinel structure containing 3d and 4f ions» and 18-42-243009: «New magnetic film nanocomposites based on layered GeO/Mn systems: synthesis, experimental and theoretical study of structural and magnetic properties». The calculations were performed with the computer resources of "Complex modeling and data processing research installations of mega-class" SRC "Kurchatovsky Institute” ( http://ckp.urcki.ru )
Аннотация: Earlier, we experimentally showed a significant effect of oxygen on the magnetic and structural properties of Mn5Ge3 due to the formation of a Nowotny phase of Mn5Ge3Ox. Here, in continuation of this study, we present a theoretical study of the magnetic and electronic properties of Mn5Ge3 and Mn5Ge3Dx (D = B, C, O). It was found that hexagonal Mn5Ge3 is a ferromagnetic metal with two nonequivalent manganese atoms in the structure. Our ab initio calculations also predict the existence of a spin-crossover in Mn5Ge3 under pressure. Impurities reduce saturation magnetization and electrical and thermal conductivity; however, the magnetic susceptibility and Curie temperature increase. Microscopic mechanisms of the effect of the impurities on the magnetic and electronic properties Mn5Ge3 are discussed.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhandun V. S., Zamkova N. G., Draganyuk O. N.
Заглавие : The arising of ferromagnetism in Al-doped Mn2(Ga1−xAlx)C MAX phases
Колич.характеристики :5 с
Место публикации : J. Magn. Magn. Mater. - 2024. - Vol. 601. - Ст.172193. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2024.172193. - ISSN 18734766 (eISSN)
Примечания : Cited References: 30. - The study was funded by a grant from the Russian Science Foundation # 23-22-10020 https://rscf.ru/project/23-22-10020/, Krasnoyarsk Regional Fund of Science. The calculations were performed with the computer resources of "Complex modeling and data processing research installations of mega-class" SRC "Kurchatovsky Institute" (http://ckp.urcki.ru). The ternary phase diagrams for the calculation of formation enthalpies were taken from Materials Project (https://materialsproject.org) and OQMD (https://oqmd.org/) databases
Аннотация: The magnetic properties of ordered MAX phases Mn2(AlxGa1−x)C (x = 0.125, 0.25, 0.5, 0.75 and 0.875) have been studied within the DFT-GGA. We have found that increase of Al atom at A-site leads to the formation of the ferromagnetic phase with large magnetization of about 3.6 μB/f.u. The investigation of the phase stability is performed by comparing the total energy of the MAX phases with that of a set of competitive phases for calculation of the phase formation enthalpy. Up to a concentration of Al atoms x = 0.7 the compound remains thermodynamically stable. The exchange constants analysis shows the crucial role of exchange interactions between manganese atoms along the c-axis in forming of ferromagnetism. The magnetic transition temperature of Mn2(AlxGa1−x)C alloys increases with increase of the aluminum concentration.
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7.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Zhandun V. S., Kazak N. V.
Заглавие : Orthogonal magnetic structures of Fe5O6: representation analysis and DFT calculations
Коллективы : International Baltic Conference on Magnetism, Балтийский федеральный университет им. И. Канта
Место публикации : V International Baltic Conference on Magnetism. IBCM: Book of abstracts. - 2023. - P.172
Примечания : Cited References: 4. - РФФИ № 21-52-12033
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8.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Zhandun V. S., Kazak N. V.
Заглавие : Orthogonal magnetic structures of Fe5O6: representation analysis and DFT calculations
Коллективы : Samarkand International Symposium on Magnetism, Samarkand State University
Место публикации : Book of abstacts of Samarkand International Symposium on Magnetism (SISM-2023)/ int. adv. com. S. G. Ovchinnikov [et al.]. - 2023. - Ст.2PO-L1-18. - P.62. - ISBN 978-5-00202-320-2
Примечания : РФФИ № 21-52-12033. - Cited References: 4. - РФФИ № 21-52-12033
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhandun V. S., Kazak N. V., Vasiukov D. M.
Заглавие : Magnetic structure of Fe5O6: Group-theoretical analysis and DFT calculations
Колич.характеристики :5 с
Место публикации : JETP Lett. - 2024. - Vol. 119, Is. 4. - P.294-298. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364023604244. - ISSN 10906487 (eISSN)
Примечания : Cited References: 27. - V. Zhandun and N. Kazak acknowledge the support of the Russian Science Foundation (project no. 21-52-12033) and D. Vasiukov acknowledges the support of the Swedish Research Council (project no. 2018-04704)
Аннотация: The magnetic structure of Fe5O6 is studied using a combination of the group-theoretical analysis and DFT + U calculations of the electronic spectrum. The calculations are performed for the magnetic k = (0, 0, 0) vector. The magnetic ground state corresponds to the orthogonal ordering of two magnetic subsystems:  the magnetic moments of Fe2+/Fe3+ ions located at the octahedral sites (slabs of octahedra) are directed along the c axis and are antiferromagnetically ordered, whereas the magnetic moments of Fe2+ ions in trigonal prisms forming one-dimensional chains are directed along the b axis and are antiferromagnetically coupled along the c axis. The formation of a nonzero antiferromagnetic component of magnetic moments in the slabs of octahedra directed along the b axis is caused by the effect of magnetic chains on the three-dimensional magnetic structure.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhandun V. S., Draganyuk O. N., Zamkova N. G.
Заглавие : Magnetic structure and pressure-induced spin-crossover in Me3B2O6 (Me = Mn, Fe, Co, Ni) kotoites: Representation analysis and DFT calculations
Колич.характеристики :10 с
Место публикации : Comput. Mater. Sci. - 2024. - Vol. 236. - Ст.112859. - ISSN 09270256 (ISSN), DOI 10.1016/j.commatsci.2024.112859. - ISSN 18790801 (eISSN)
Примечания : Cited References: 25. - The study was funded by a grant from the Russian Science Foundation # 22-22-20024 https://rscf.ru/project/22-22-20024/, Krasnoyarsk Regional Fund of Science. The calculations were performed with the computer resources of “Complex modeling and data processing research installations of mega-class” SRC “Kurchatovsky Institute” (http://ckp.urcki.ru). VZ thanks Dr. Natalia Kazak and Oksana Draganyuk for help in preparing the manuscript, useful discussions and valuable advices
Аннотация: The magnetic and electronic properties of transition metal borates Me3B2O6 (Me = Mn, Fe, Co, Ni) with kotoite structure have been investigated at ambient and high pressures via a combination of representation analysis and density functional theory (DFT + U) calculations. Several magnetic configurations corresponding to the different irreducible representations have been considered. The total-energy calculations reveal that the magnetic ground state of Me3B2O6 kotoites is composition-dependent. The lowest energy magnetic phase of manganese and nickel kotoites is characterized by the antiferromagnetic ordering of the transition metal magnetic moments along the c- axis and along the b-axis for cobalt and iron kotoites. The magnetic cell of Ni3B2O6 kotoite corresponds to k = (1/2, 0, 1/2) vector and four time larger than the unit cell. The calculated exchange constants indicate the competition between ferromagnetic and antiferromagnetic interactions. At a critical pressure, Me ions undergo a high-spin to low-spin state crossover. This magnetic moments collapse is analyzed in terms of change in electronic structure under pressure.
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