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Shut V.N.,Institute of Technical Acoustics | Syrtsov S.R.,Institute of Technical Acoustics | Trublovsky V.L.,Institute of Technical Acoustics | Il'Yuschenko D.A.,Institute of Technical Acoustics | Troyanchuk I.O.,Scientific Practical Materials Research Center
Ferroelectrics | Year: 2014

Ceramics of composition Ba1-xLaxTiO3 were prepared by two-step sintering method. The average grain size of the sintered samples were 300 nm (for x = 0.025) and 500 nm (for x = 0.05). Relative densities of these samples were 92.8%TD and 92.3%TD. Despite the small grain size, the magnitude of dielectric permittivity of ceramics has higher value in comparison with coarse-grained materials sintered by standard technology (with grain size >1 μm). © 2014 Copyright Taylor & Francis Group, LLC.


Gusakov V.,Scientific Practical Materials Research Center | Gusakova J.,EPAM Systems | Markevich V.P.,University of Manchester
Proceedings of International Conference NANOMEETING 2011: Physics, Chemistry and Applications of Nanostructures - Reviews and Short Notes | Year: 2011

Quantum-chemical modeling of structural stability of Si nanowires is presented. Formation and diffusion of intrinsic point defects in the nanowires have also been studied. The significant decrease of the Frenkel pairs formation energy in nanowires as compared with bulk crystalline silicon was found.Copyright © 2011 by World Scientific Publishing Co. Pte. Ltd.


Popescu A.-M.J.,Ilie Murgulescu Institute of Physical Chemistry | Constantin V.,Ilie Murgulescu Institute of Physical Chemistry | Olteanu M.,Ilie Murgulescu Institute of Physical Chemistry | Demidenko O.,Scientific Practical Materials Research Center | Yanushkevich K.,Scientific Practical Materials Research Center
Revista de Chimie | Year: 2011

The present study deals with electrodeposition of copper from four different choline chlorides (ChCl) based ionic liquids (IL) as environmentally friendly electrolytes. Firstly, we prepared the ChCl-A (1:2 and 1:1) M based ionic liquids (A=Urea, Malonic acid, Oxalic acid, Ethylene glycol) and then measured the density, viscosity and conductivity of these mixtures. These ionic liquids have the great advantage of air and moisture stability in time. The solubility of CuCl2anh and electrodeposition of Cu in these mixtures were performed. The working parameters along with the time and appearance of the obtained copper deposits were followed during the electrolysis process. Finally, the best deposits were studied by micrographic techniques By X-ray method in CuK -radiation at room temperature is studied the crystal structure features of the cooper deposited on substrate from industrial steel using the method described in works. The thickness of the coating is determined. The unit crystalline cell values of thin cooper layers on steel are determined. The influence of the elecrodeposition conditions on crystalline ordering is also studied. Of the four electrolytes studied it was found that better deposits (fine, homogenous and adherent) were obtained in ChCl-Oxalic acid and ChCl-Ethylen glycol.


Constantin V.,Ilie Murgulescu Institute of Physical Chemistry | Neacsu E.I.,Ilie Murgulescu Institute of Physical Chemistry | Popescu A.M.,Ilie Murgulescu Institute of Physical Chemistry | Galyas A.,Scientific Practical Materials Research Center | And 2 more authors.
Acta Physica Polonica A | Year: 2015

The corrosion action for bulk and thin Nd2Fe14B films magnets in different corrosion media was studied. The thin Nd-Fe-B films of 100 nm ≤ d ≤ 1000 nm were deposited on glass substrate by "flash" evaporation method. The structure and microstructure of the samples were studied by X-ray diffraction analysis, scanning electron microscopy. The temperature dependence of the magnetization before and after corrosion action was carried out by ponderomotive method in the temperature range 80 ≤ T ≤ 800 K. It is shown that the specific magnetizations of the thin Nd-Fe-B films with d ≥ 1000 nm are comparable to those measured for the powder samples. The values of the coercive and saturation fields were determined from the hysteresis loops measurements.


Popescu A.M.,Ilie Murgulescu Institute of Physical Chemistry | Neacsu E.I.,Ilie Murgulescu Institute of Physical Chemistry | Yanushkevich K.,Scientific Practical Materials Research Center | Constantin V.,Ilie Murgulescu Institute of Physical Chemistry
Surface and Interface Analysis | Year: 2014

Electroless Zn-Ni-P thin films were deposited on low carbon steel from an alkaline non-cyanide aqueous electrolyte. The newly developed ternary alloys structure and microstructure investigations were carried out via X-ray diffraction and SEM. Chemical composition of the coatings was investigated via energy dispersive spectroscopy. Polarization tests were used to study the corrosion properties of the coatings in a 3.5 wt.% NaCl solution. The results confirmed the high corrosion resistance of Zn-Ni-P alloy plated steel sheet. The surface analysis of the thin film samples before and after corrosion was performed by XPS. The incorporation of Zn in Ni-P thin film is proven for all initial samples to be as a mixture of zinc and zinc oxide, while nickel exists in +2 and +3 oxidized states. A passive film of a mixture of oxide and hydroxide of zinc and nickel forms on the surface and prevents the Zn-Ni-P thin films from corrosion. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.


Popescu A.M.,Ilie Murgulescu Institute of Physical Chemistry | Yanuskevich K.,Scientific Practical Materials Research Center | Demidenko O.,Scientific Practical Materials Research Center | Calderon Moreno J.M.,Ilie Murgulescu Institute of Physical Chemistry | And 2 more authors.
Central European Journal of Chemistry | Year: 2013

Thin films of Zn-Ni-P on a copper substrate were synthesized by electrodeposition from chloride baths. It was found that the diffraction reflections of the crystal structure of Zn-Ni-P thin layers occur at thicknesses d ≥ 5 μm. The X-ray diffraction studies results confirm the formation in the Zn-Ni-P films of ZnNi10P3 compound. The morphology of the obtained films was analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS). The films are continuous and have a typical topography with many homogeneous globular features. EDS confirmed the formation of Zn-Ni-P coating only in 2 samples with Zn:Ni:P atomic ratios of 1:8:4 and 4:8:3, respectively. X-ray Photoelectron Spectroscopy (XPS) revealed the chemistry and the thickness of the studied thin films. At room temperature and thickness d ≥ 5 μm the investigated thin layers exhibit high values of the specific magnetizations in the range (25-37) A m2 kg -1, leading to the potential use in devices, appliances and electronics. The Curie temperature values of the synthesized Zn-Ni-P films were determined. It was found that by heating Zn-Ni-P thin layers of thicknesses d ≥ 5 μm up to a temperature T=900 K an interaction was detected with the copper substrate leading to a lower specific magnetization. [Figure not available: see fulltext.] © 2013 Versita Warsaw and Springer-Verlag Wien.


Aplesnin S.S.,Siberian State Aerospace University | Romanova O.B.,RAS Kirensky Institute of Physics | Yanushkevich K.I.,Scientific Practical Materials Research Center
Physica Status Solidi (B) Basic Research | Year: 2015

The electric and magnetic properties of anion-substituted antiferromagnetic MnSe1-xTex (0.1≤x≤0.4) semiconductors in the 77-700K temperature range and magnetic fields under 1T are studied. In the MnSe1-xTex solid solutions, negative magnetoresistance in the vicinity of the Néel temperature for x=0.1 and for composition with x=0.2 in the paramagnetic range below 270K is revealed. A dependence of the magnetic susceptibility versus the prehistory of the samples is found. The model of localized spin-polarized electrons with the localization radius depending on the magnetic field is proposed for x=0.1. In the paramagnetic range, the negative magnetoresistance and the behavior of magnetic moment are a result of orbital glass formation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Goncharova O.,B. I. Stepanov Institute of Physics | Gremenok V.,Scientific Practical Materials Research Center
Proceedings of International Conference NANOMEETING 2011: Physics, Chemistry and Applications of Nanostructures - Reviews and Short Notes | Year: 2011

Three kinds of thin films were prepared: the microcrystalline In 2S3 films of 10-800 nm thicknesses, the textured multilayer films consisting of CdS nanocrystals, the textured multilayer films of various layer thickness and composition. Their investigations performed have shown the multilayer films to be the best as low-cost photovoltaic structures.Copyright © 2011 by World Scientific Publishing Co. Pte. Ltd.


Aplesnina S.S.,Siberian State Aerospace University | Kretinin V.V.,Siberian State Aerospace University | Ostapenko A.A.,Siberian State Aerospace University | Galyas A.I.,Scientific Practical Materials Research Center | Yanushkevich K.L.,Scientific Practical Materials Research Center
Solid State Phenomena | Year: 2014

Multiferroics based on BiFeO3 with spatially-modulated antiferromagnetic structure are investigated. The goal of this work is to define possibility of orientation phase transitions in magnetic and electric system by replacing Bi with 4f Nd ion depending on temperature in external magnetic field. On NdxBi1-xFeO3 films the measurements of permittivity, loss tangent at frequences 100 Hz < ω < 105 Hz and at temperatures 300 K{cyrillic} < T < 1000 K without magnetic field and in magnetic field with H=0.8 T{cyrillic} were made. A drop in temperature dependence of permittivity in magnetic field was found. Magnetoelectric properties can be explained in model of changing of magnetic structure in magnetic field as a result of interaction of electric and magnetic subsystems. © (2014) Trans Tech Publications, Switzerland.


Aplesnin S.,Siberian State Aerospace University | Galyas A.,Scientific Practical Materials Research Center | Demidenko O.,Scientific Practical Materials Research Center | Makovetskii G.,Scientific Practical Materials Research Center | And 2 more authors.
Acta Physica Polonica A | Year: 2015

The synthesis of polycrystalline Mn1-xGdxSe solid solutions is carried out by solid state reaction method followed by quenching from the temperature of 1370 K. The X-ray diffraction studies realized at 300 K revealed that the structure of the single phase samples in the 0 < x < 0:15 concentration range is identified on base a face centered cubic crystal cell of Fm3m space group. The heating of the solid solutions to 900 K does not affect on the magnetic susceptibility as the dependences is identical to the measurements in the "heating-cooling" regime. Comparing the research results of magnetic properties of the Mn1-xGdxSe solid solutions with those of Mn1-xGdxS solid solutions, we can conclude that substitution of manganese ions by gadolinium in manganese selenide lead to more changes in the basic magnetic characteristics than in manganese sulfide.

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