125 research outputs found

    Orientation, substructure, and optical properties of rutile films

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    The orientation, optical properties, and substructure of rutile films prepared by thermal and pulsed photon assisted oxidation of single crystal Ti films were investigated by transmission electron micros copy, optical spectroscopy, and high energy electron diffractionyesBelgorod State Universit

    Electrical properties and local domain structure of LiNbO3 thin film grown by ion beam sputtering method

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    The nanocrystalline ferroelectric LiNbO3 films on (001) Si substrates with the random orientation of polycrystalline grains and the predominance of the grains with lateral orientation of the polar axis were grown using the ion beam sputtering method. The remanent polarization and the coercive field are 12 μC/cm2 and 29 kV/cm, respectively. The thermal annealing leads to the coarsening of the grains. The appearance of the "local texture," which gives rise to the unipolarity of the heterostructures caused by the predominance of the one direction in the vertical component of the spontaneous polarization, is investigated. © The Chinese Society for Metals and Springer-Verlag Berlin Heidelberg

    Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals

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    We have studied the ferroelectric nanodomain formation in single crystals of strontium barium niobate Sr 0.61Ba 0.39Nb 2O 6 using piezoelectric force microscopy and Raman confocal microscopy. The nanodomain structures have been created by application of the uniform electric field at room temperature. Four variants of nanodomain structure formation have been revealed: (1) discrete switching, (2) incomplete domain merging, (3) spontaneous backswitching, and (4) enlarging of nanodomain ensembles. Kinetics of the observed micro- and nanodomain structures has been explained on the basis of approach developed for lithium niobate and lithium tantalate crystals. © 2012 American Institute of Physics

    Orientation, substructure, and optical properties of rutile films

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    The orientation, optical properties, and substructure of rutile films prepared by thermal and pulsed photon assisted oxidation of single crystal Ti films were investigated by transmission electron micros copy, optical spectroscopy, and high energy electron diffractionyesBelgorod State Universit

    Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals

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    We have studied the ferroelectric nanodomain formation in single crystals of strontium barium niobate Sr 0.61Ba 0.39Nb 2O 6 using piezoelectric force microscopy and Raman confocal microscopy. The nanodomain structures have been created by application of the uniform electric field at room temperature. Four variants of nanodomain structure formation have been revealed: (1) discrete switching, (2) incomplete domain merging, (3) spontaneous backswitching, and (4) enlarging of nanodomain ensembles. Kinetics of the observed micro- and nanodomain structures has been explained on the basis of approach developed for lithium niobate and lithium tantalate crystals. © 2012 American Institute of Physics

    Investigation local switching and self-organization effects on non-polar cuts of lithium niobate

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    The equipment of the Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (Grant 14-12-00826)

    Synthesis and Cytotoxic Effect of 1-Aryl-Substituted-6-Imino-2,7-Dioxabicyclo[3.2.1]Octane-4,4,5-Tricarbonitriles

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    The work was carried out within the framework of scholarship SP-127.2016.4 from the President of the Russian Federation for young scientists and graduate students

    Oxide charge evolution under crystallization of amorphous Li–Nb–O films

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    Li–Nb–O amorphous films were deposited onto Si substrates by the radio-frequency magnetron sputtering method in an Ar environment and an Ar(60%)+O2(40%) gas mixture. A positive effective fixed oxide charge Qeff having negative, -Qeff, and positive, +Qeff, components, exists in the as-grown heterostructures. -Qeff is located near the substrate/film interface, whereas + Qeff is determined by a deficit of Li and O (vacancies) in the bulk of Li–Nb–O films. As-grown films crystallized under thermal annealing (TA) at temperatures up to 600 °C and revealed the formation of polycrystalline LiNbO3. TA at about 520 °C resulted in the formation of the second phase LiNb3O8, increasing + Qeff, and compensating -Qeff entirely. The dielectric constants of the as-grown films exhibit two peaks at the annealing temperatures of 450 °C and 550 °C, which are attributed to the total crystallization and recrystallization of the LN films under TA, respectively. © 2020 The AuthorsRussian Foundation for Basic Research, RFBR: 18-29-11062, 18-32-00959This research was supported by the Russian Foundation for Basic Research (Grant № 18-29-11062 and Grant № 18-32-00959 ). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” of the Ural Federal University was used

    Strange Behaviour of Transport Properties in Novel Metal Thiocyanate Based Ionic Liquids

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    Financiado para publicación en acceso aberto: Universidade da Coruña/CISUGThe following are the Supplementary data to this article: https://ars.els-cdn.com/content/image/1-s2.0-S0167732221018882-mmc1.docx[Abstract] In a previous paper some of us presented the structure and some properties of a new family of ionic liquids, ILs, with a common cation, 1-butyl-3-methyl imidazolium (the popular [C4C1Im]⁺ or [BMIM]⁺) and a variety of anions based in thiocyanate (SCN)¯: one reference sample and ten with anionic metal complexes of different valences: Al¹¹¹, Mn¹¹, Fe¹¹, Cr¹¹¹, Ni¹¹, Hg¹¹, Zn¹¹, Co¹¹ and Cu¹, resulting, respectively, [BMIM](SCN), [BMIM]₃ Al(SCN)₆, [BMIM]₄ Mn(SCN)₆, [BMIM]₃ Fe(SCN)₆, [BMIM]₃ Cr(SCN)₆, [BMIM]₄ Ni(SCN)₆, [BMIM]₂ Hg(SCN)₄, [BMIM]₂ Zn(SCN)₄, [BMIM]₂ Co(SCN)₄ and [BMIM]₃ Cu(SCN)₄. In this paper we show experimental measurements of electrical conductivity of these ILs in a broad temperature range (about 90 K). Viscosity has been measured for six compounds in a wide temperature range. In addition, the diffusion coefficient for both ions forming the IL has been measured for some of the samples using NMR-Dosy technique. In spite of being very similar compounds from a chemical point of view, they present very different transport property values. Thus, viscosity varies more than two orders of magnitude among those metal thiocyanate ILs, being the highest for the compound with Al and the lowest for that with Hg. Moreover, differences between ionic conductivity and diffusion coefficient values extend more than one order of magnitude among the thiocyanate ILs. These three properties will be related in pairs, thus through Walden’s rule we compare molar conductivity and fluidity, while using Kohlrausch’s law and Nerst-Einstein equation molar conductivity and diffusion coefficient are related. Also, diffusion coefficient and fluidity (the inverse of viscosity) are compared by means of Stokes-Einstein relationship. In addition, we calculate the Laity interionic friction coefficients for both anions of the IL with Hg. Finally, a theoretical model is suggested to explain all the experimental evidences reported.We acknowledge the financial support of Ministerio de Economía y Competitividad MINECO) (MAT2017-86109-P and MAT2017-89239-C2-(1.2)-P); and Xunta de Galicia (AGRU 015/11. GRC ED431C 2016/001 and ED431D 2017/06). All these research projects were partially supported by FEDER. Also, D.A. acknowledges Gil Dávila Foundation for his postgraduate grant. Funding for open access charge: Universidade da Coruña/CISUG.Xunta de Galicia; ED431C 2016/001Xunta de Galicia; ED431D 2017/06https://ars.els-cdn.com/content/image/1-s2.0-S0167732221018882-mmc1.doc

    Structural Characterization by NMR Procedure of C₄C₁Pyrr TFSI Doped with Lithium TFSI Salt in Liquid and Gel States

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    [Abstract] Ionic liquids represent a viable option as electrolytes for electrochemical applications such as energy storage devices, due to their high ionic conductivity and wide electrochemical window. However, liquid electrolytes present important problems of safety and performance, and encapsulation in a solid matrix can be a good solution to improve it. In this work, changes in the structure of the mixtures of ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and lithium bis(trifluoromethylsulfonyl)imide against the concentration of the salt (0, 0.1, and 1.5 molal), and the effect of nanoconfinement through gelation process were studied using NMR technique.This work was supported by the Spanish Ministry of Economy and Competitiveness and FEDER Program through the projects MAT2014-57943-C3-1-P, MAT2014-57943-C3-3-P, MAT2017-89239-C2-1-P as well as by Xunta de Galicia through GRC ED431C 2020/10 project and the Galician Network of Ionic Liquids (ReGaLIs) ED431D 2017/06. P. Vallet and J. J. Parajó thank funding support of FPI Program from the Spanish Ministry of Science, Education and Universities and I2C postdoctoral Program of Xunta de Galicia, respectivelyXunta de Galicia; ED431C 2020/10Xunta de Galicia; ED431D 2017/0
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