Персона: Емельянова, Ольга Владимировна
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Емельянова
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Ольга Владимировна
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- ПубликацияТолько метаданныеAntiferromagnetic resonances in twinned EuFe2 As2 single crystals(2022) Golovchanskiy, I. A.; Abramov, N. N.; Vlasenko, V. A.; Pervakov, K.; Shchetinin, I. V.; Dzhumaev, P. S.; Emelyanova, O. V.; Baranov, D. S.; Kalashnikov, D. S.; Polevoy, K. B.; Pudalov, V. M.; Stolyarov, V. S.; Джумаев, Павел Сергеевич; Емельянова, Ольга ВладимировнаIn this paper, we report the results of magnetic resonance spectroscopy of EuFe2As2 single crystals. We observe magnetic resonance responses, which are attributed to antiferromagnetic resonances of the Eu sublattice with orthorhombic crystal structure and with different orientations of twin domains relative to the external field. We confirm the validity of the recently proposed spin Hamiltonian with anisotropic Eu-Eu exchange interaction and biquadratic Eu-Fe exchange interaction. © 2022 American Physical Society.
- ПубликацияТолько метаданныеMagnetic resonances in EuSn2As2 single crystal(2022) Golovchanskiy, I. A.; Maltsev, E. I.; Shchetinin, I. V.; Vlasenko, V. A.; Dzhumaev, P. S.; Pervakov, K. S.; Emelyanova, O. V.; Tsvetkov, A. Y.; Abramov, N. N.; Pudalov, V. M.; Stolyarov, V. S.; Джумаев, Павел Сергеевич; Емельянова, Ольга ВладимировнаIn this work, we report the broad-band ferromagnetic resonance spectroscopy of EuSn2As2 single crystals at different temperatures in combination with magnetization measurements and structural characterization. We observe conventional collective acoustic resonance mode of the A-type antiferromagnetic canted state in the Eu sub-lattice, and its transition to the paramagnetic resonance above the ordering temperature. Furthermore, we observe reproducibly additional well-defined spectral line. The origin of the additional line remains unclear. However, its temperature dependence associates it with the magnetism in the Eu sub-lattice. © 2022 Elsevier B.V.
- ПубликацияТолько метаданныеPhysical Vapor Deposition Features of Ultrathin Nanocrystals of Bi2(TexSe1- x)3(2022) Yakovlev, D. S.; Lvov, D. S.; Emelyanova, O. V.; Dzhumaev, P. S.; Shchetinin, I. V.; Skryabina, O. V.; Egorov, S. V.; Ryazanov, V. V.; Golubov, A. A.; Roditchev, D.; Stolyarov, V. S.; Емельянова, Ольга Владимировна; Джумаев, Павел СергеевичStructural and electronic properties of ultrathin nanocrystals of chalcogenide Bi2(Tex Se1-x)3 were studied. The nanocrystals were formed from the parent compound Bi2Te2Se on as-grown and thermally oxidized Si(100) substrates using Ar-assisted physical vapor deposition, resulting in well-faceted single crystals several quintuple layers thick and a few hundreds nanometers large. The chemical composition and structure of the nanocrystals were analyzed by energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, electron backscattering, and X-ray diffraction. The electron transport through nanocrystals connected to superconducting Nb electrodes demonstrated Josephson behavior, with the predominance of the topological channels [Stolyarov et al. Commun. Mater., 2020, 1, 38]. The present paper focuses on the effect of the growth conditions on the morphology, structural, and electronic properties of nanocrystals.
- ПубликацияОткрытый доступЛабораторный практикум "Материаловедение термоядерных реакторов"(НИЯУ МИФИ, 2019) Калин, Б. А; Польский, В. И.; Якушин, В. Л.; Волков, Н. В.; Чернов, И. И.; Джумаев, П. С.; Стальцов, М. С.; Емельянова, О. В.; Емельянова, Ольга Владимировна; Стальцов, Максим Сергеевич; Джумаев, Павел Сергеевич; Польский, Валерий ИгоревичВ практикуме представлены теоретические основы материаловедения термоядерных реакторов, включая, условия работы материалов в различных термоядерных реакторах, радиационную стойкость материалов рабочей камеры реактора под воздействием излучения горячей плазмы, поведение легких газов в материалах и перспективные материалы первой стенки термоядерного реактора. Лабораторный практикум состоит из трех лабораторных работ по дисциплине «Специальные вопросы материаловедения ТЯР». Даны методические указания по выполнению практических заданий по изучению структуры и свойств перспективных материалов ТЯР в условиях эксплуатации. Пособие рекомендуется студентам старших курсов, обучающихся по специальности «Материаловедение и технологии материалов» и также студентам других смежных специализаций.
- ПубликацияОткрытый доступMagnetization Dynamics in Proximity-Coupled Superconductor-Ferromagnet-Superconductor Multilayers. II. Thickness Dependence of the Superconducting Torque(2023) Golovchanskiy, I. A.; Abramov, N. N.; Emelyanova, O. V.; Shchetinin, I. V.; Емельянова, Ольга Владимировна
- ПубликацияОткрытый доступFerromagnet/Superconductor Hybrid Magnonic Metamaterials(2019) Golovchanskiy, Igor A.; Abramov, Nikolay N.; Stolyarov, Vasily S.; Golubov, Alexander A.; Dzhumaev, Pavel S.; Emelyanova, Olga V.; Джумаев, Павел Сергеевич; Емельянова, Ольга ВладимировнаIn this work, a class of metamaterials is proposed on the basis of ferromagnet/superconductor hybridization for applications in magnonics. These metamaterials comprise of a ferromagnetic magnon medium that is coupled inductively to a superconducting periodic microstructure. Spectroscopy of magnetization dynamics in such hybrid evidences formation of areas in the medium with alternating dispersions for spin wave propagation, which is the basic requirement for the development of metamaterials known as magnonic crystals. The spectrum allows for derivation of the impact of the superconducting structure on the dispersion: it takes place due to a diamagnetic response of superconductors on the external and stray magnetic fields. In addition, the spectrum displays a dependence on the superconducting critical state of the structure: the Meissner and the mixed states of a type II superconductor are distinguished. This dependence hints toward nonlinear response of hybrid metamaterials on the magnetic field. Investigation of the spin wave dispersion in hybrid metamaterials shows formation of allowed and forbidden bands for spin wave propagation. The band structures are governed by the geometry of spin wave propagation: in the backward volume geometry the band structure is conventional, while in the surface geometry the band structure is nonreciprocal and is formed by indirect band gaps.
- ПубликацияОткрытый доступBubble-to-void transition promoted by oxide nanoparticles in ODS-EUROFER steel ion implanted to high He content(2021) Gentils, A.; Vladimirov, P. V.; Golovchanskiy, I. A.; Lindau, R.; Emelyanova, O.; Borodin, V. A.; Ganchenkova, M. G.; Dzhumaev, P. S.; Емельянова, Ольга Владимировна; Бородин, Владимир Алексеевич; Джумаев, Павел Сергеевич© 2020The paper deals with a detailed study of He-filled cavity ensemble development in ODS-EUROFER steel implanted with 10 keV helium ions to a high peak concentration of 8.5 × 103 appm both with and without simultaneous irradiation with 4 MeV gold ions, which allowed us to strongly vary the ratios of dpa/He introduction. The subsequent transmission electron microscopy examination reveals excellent radiation stability of He-implanted sample in the single-beam implantation mode. In contrast, after the simultaneous dual-beam irradiation a bubble-to-void transition was observed for bubbles that were associated with yttria nanoparticles. The relative importance of different He bubble families observed in the He-implanted samples for the swelling accumulation is quantitatively assessed, emphasizing the potential risks of abrupt swelling acceleration in the case of bubble-to-void transition launched by nanoparticles. A model of bubble-to-void transition for gas bubbles associated with spherical second-phase particles is developed and used to rationalize experimental observations.
- ПубликацияОткрытый доступMicrostructural evolution in ODS-EUROFER steel caused by high-dose He ion implantations with systematic variation of implantation parameters(2023) Emelyanova, O. V.; Gentils, A.; Borodin, V. A.; Dzhumaev, P. S.; Емельянова, Ольга Владимировна; Бородин, Владимир Алексеевич; Джумаев, Павел СергеевичThe paper presents a detailed analysis of helium (He) bubble development in ODS-EUROFER steel caused by helium ion implantation in different regimes, with a particular attention to the role of the oxide nanoparticles in promoting the growth of He bubbles, helium accumulation and gas-driven swelling. The Transmission Electron Microscopy (TEM) characterization of steel samples implanted applying systematic variation of experimental parameters has allowed clarifying the trends of the bubble microstructure evolution depending on the implantation dose, flux, and sample temperature. It was found that in all investigated implantation regimes He bubbles formed both in the grain bulk and on various structural defects (dislocations, grain boundaries, oxide particles and carbide precipitates), but the sizes and densities of bubbles in different bubble populations were sensitive to particular irradiation conditions. In the majority of cases the main traps for implanted helium and the main contributors to the estimated swelling were bubbles associated with grain boundaries, though in some cases (high implantation dose or lower temperature) the bubbles in the grain bulk were competitive with the grain boundary bubble population. Oxide particles in ODS-EUROFER were found to be excellent nucleation sites for He bubbles and practically each observed particle hosted a single relatively large bubble, sometimes as large as the particle itself. However, the contribution of oxide-associated bubbles to the estimated swelling and He inventory was found to be minor as compared to other bubble populations because of a relatively low number density of nano-oxides. Comparison of ODS-EUROFER and EUROFER 97 samples implanted with He ions in identical regimes has demonstrated lower efficiency of ODS-EUROFER for accumulating implanted helium in bubbles and noticeably higher share of helium atoms trapped in the vacancy defects invisible by TEM.
- ПубликацияОткрытый доступJosephson current mediated by ballistic topological states in Bi2Te2.3Se0.7 single nanocrystals(2020) Stolyarov, V. S.; Yakovlev, D. S.; Kozlov, S. N.; Skryabina, O. V.; Emelyanova, O. V.; Dzhumaev, P. S.; Емельянова, Ольга Владимировна; Джумаев, Павел Сергеевич© 2020, The Author(s).Superconducting proximity devices using low-dimensional semiconducting elements enable a ballistic regime in the proximity transport. The use of topological insulators in such devices is considered promising owing to the peculiar transport properties these materials offer, as well the hope of inducing topological superconductivity and Majorana phenomena via proximity effects. Here we demonstrate the fabrication and superconducting properties of proximity Josephson devices integrating nanocrystals single of Bi2Te2.3Se0.7 with a thickness of a few unit cells. Single junctions display typical characteristics of planar Josephson devices; junctions integrating two nanocrystals behave as nanodimensional superconducting quantum interference devices. A peculiar temperature and magnetic field evolution of the Josephson current along with the observed excess current effect point towards the ballistic proximity regime of topological channels. This suggests the proposed devices are promising for testing topological superconducting phenomena in two-dimensions.