OAO Fomos Materials

Moscow, Russia

OAO Fomos Materials

Moscow, Russia
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Buzanov O.A.,OAO Fomos Materials | Voronova M.I.,Moscow Institute of Steel And Alloys | Zabelina E.V.,Moscow Institute of Steel And Alloys | Kozlova A.P.,Moscow Institute of Steel And Alloys | And 4 more authors.
Inorganic Materials | Year: 2017

La3Ga5.5Ta0.5O14 crystals were grown in pure argon and in an argon + 2% oxygen atmosphere. The growth atmosphere significantly effects the elemental composition of the crystals, their color, and the genesis and intensity of absorption bands in the ultraviolet, visible, and infrared spectral regions. Two types of defects were identified in the crystals: planar interstitial defects and nearly spherical vacancy-type defects. © 2017, Pleiades Publishing, Ltd.


Roshchupkin D.V.,HIGH-TECH | Irzhak D.V.,HIGH-TECH | Emelin E.V.,HIGH-TECH | Fahrtdinov R.R.,HIGH-TECH | And 4 more authors.
IEEE International Ultrasonics Symposium, IUS | Year: 2012

A five-component crystal of lanthanum-gallium silicate family Ca3TaGa3Si2O14 (CTGS) was grown by the Czochralski method. The CTGS crystal, like langasite crystals La3Ga5SiO14, possesses unique temperature properties and the fewer number of the Ga atoms in the unit cell makes the density much lower and, consequently, increases the velocity of acoustic wave propagation. The unit cell parameters were determined by the powder diffraction technique. The defects in the CTGS crystal structure were studied by X-ray topography which enables the visualization of growth banding characteristics of crystal grown by Czochralski method. Surface acoustic wave (SAW) propagation in the CTGS crystal was investigated by the high-resolution X-ray diffraction method. The velocities of propagation and power flow angles of SAW in the Y-and X-cuts of the CTGS crystal were determined from the X-ray diffraction spectra. © 2012 IEEE.


Kugaenko O.M.,National University of Science and Technology "MISIS" | Uvarova S.S.,National University of Science and Technology "MISIS" | Petrakov V.S.,Economic Power Institute | Buzanov O.A.,OAO Fomos Materials | And 3 more authors.
Russian Metallurgy (Metally) | Year: 2013

The microstructure of piezoelectric lanthanum-gallium tantalite single crystals is shown to change substantially during cyclic mechanical actions at room temperature and during thermal shock: the dislocation density increases, twinning takes place, and a mesostructure forms. This effect is related to the appearance of piezoelectric fields, which significantly decrease the temperature of the onset of plastic deformation of these brittle single crystals, during mechanical actions. © 2013 Pleiades Publishing, Ltd.


Kugaenko O.M.,National University of Science and Technology "MISIS" | Uvarova S.S.,National University of Science and Technology "MISIS" | Krylov S.A.,National University of Science and Technology "MISIS" | Senatulin B.R.,National University of Science and Technology "MISIS" | And 4 more authors.
Bulletin of the Russian Academy of Sciences: Physics | Year: 2012

The thermophysical parameters (thermal diffusivity χ, heat conductivity λ, thermal expansion, and specific heat c p coefficients) of single crystals from the langasite family are investigated in the basic crystallographic directions of X, Y, and Z in temperature range of 300 to 1300 K. The temperature dependences of the parameters are determined. It is found that their anisotropy decreases with temperature. © 2012 Allerton Press, Inc.


Kozlova N.S.,National University of Science and Technology "MISIS" | Buzanov O.A.,OAO Fomos Materials | Zabelina E.V.,National University of Science and Technology "MISIS" | Bykova M.B.,National University of Science and Technology "MISIS" | And 2 more authors.
Bulletin of the Russian Academy of Sciences: Physics | Year: 2014

Results from studying the effect conditions of growth (atmosphere of growth) and subsequent treatment (annealing in air and in vacuum) have on the optical properties of crystalline lanthanum-gallium tantalate and possible processes that occur in the crystal structure upon the emergence of defects (e.g., the formation of color centers) are presented. Luminescence characteristics of undoped single langatate crystals are determined for the first time. © 2014, Allerton Press, Inc.


Kugaenko O.M.,National University of Science and Technology "MISIS" | Torshina E.S.,National University of Science and Technology "MISIS" | Buzanov O.A.,OAO Fomos Materials | Sakharov S.A.,OAO Fomos Materials
Bulletin of the Russian Academy of Sciences: Physics | Year: 2014

The microhardness of single crystals of the La3Ga5SiO14, La3Ta0.5Ga5.5O14, Ca3TaGa3Si2O14 family of lantanum-gallium silicates of trigonal symmetry class 32 of space group P321 is studied using the Knupp approach. The anisotropy of grade I microhardness (the polar dependence of microhardness on an indentor’s position relative to the crystallographic directions in the plane of measurement) is revealed in crystallographic planes (11 20),(01 10), (0001). The anisotropy of cracking resistance is revealed by measuring the stress intensity of crystals, allowing us to determine the direction and plane of a fracture in single crystals of the langasite family. © 2014, Allerton Press, Inc.


Medvedev A.,OAO Fomos Materials | Zabelin A.,OAO Fomos Materials | Bazalevskaya S.,OAO Fomos Materials | Buzanov O.,OAO Fomos Materials | And 4 more authors.
2013 Joint European Frequency and Time Forum and International Frequency Control Symposium, EFTF/IFC 2013 | Year: 2013

Resonators manufactured on Ca3TaGa3Si 2O14 single crystals (CTGS) operating in a thickness shear mode were investigated. The frequency temperature characteristics of the rotated Y-cut based resonators were measured. The resonators operated at the crystal elements with angle cut -21°20' have frequency deviation less than 120 ppm in the operating temperature range from -60 up to 85°C. The temperature coefficient of frequency of the second order is close to -0.022 ppm/°C2. It is shown that maintaining turnover point of the frequency temperature characteristic within the range of ±1 °C requires accuracy of the crystal element manufacturing not worse than ±1.5 angular minutes for resonators with Ag electrodes. The dependence of the Bechmann's number on electrode thickness was calculated. It was discovered that for Ag electrode coating with electrode thickness of 200 nm, the single-response characteristic of the resonator can be obtained if the electrode size (lx) does not exceed 12 thicknesses of the crystal element. With the limiting value of the relative electrode size equaling lx/t =12.3, the relative resonance interval is 1%, while the capacitance ratio is 47 units. © 2013 IEEE.


Kozlova N.S.,National University of Science and Technology "MISIS" | Busanov O.A.,OAO Fomos Materials | Zabelina E.V.,National University of Science and Technology "MISIS" | Kozlova A.P.,National University of Science and Technology "MISIS" | Kasimova V.M.,National University of Science and Technology "MISIS"
Crystallography Reports | Year: 2016

Crystals of cerium-doped gadolinium–gallium–aluminum garnet have been grown by the Czochralski method. The transmission and reflection spectra of these crystals in the wavelength range of 250–800 nm have been obtained by optical spectroscopy. Refractive indices are calculated based on the measured Brewster angles, the experimental results are approximated using the Cauchy equation, and a dispersion dependence is obtained. © 2016, Pleiades Publishing, Inc.


Kurosawa S.,Tohoku University | Kitahara M.,Tohoku University | Yokota Y.,Tohoku University | Hishinuma K.,Tohoku University | And 5 more authors.
IEEE Transactions on Nuclear Science | Year: 2014

In order to search for a new scintillation material consisting of tantalum (Ta) with a high atomic number of 73, we have investigated scintillation properties of langasite type crystal containing Ta. Non-doped Ca 3TaGa3Si2O14 (CTGS), which is well known as a piezoelectric material, was grown by the Czochralski method. Radio-luminescence spectrum of this crystal peaked around 340 nm. Its light output was approximately 1,200 photons/MeV. This crystal is expected to be a scintillation host material. © 2014 IEEE.


Roschupkin D.V.,Russian Academy of Sciences | Emelin E.V.,Russian Academy of Sciences | Buzanov O.A.,OAO FOMOS Materials
Russian Microelectronics | Year: 2014

The process of repolarization of LiTaO3 ferroelectric crystal by direct electron-beam lithography is studied. The possibility is considered of the formation of a domain structure with domain size ∼1 μm. It has been shown that in the 127° Y′-cross section of the LiTaO3 crystal ferroelectric domains form at an angle of 37° to the crystal surface and they grow from the negative surface to the positive along the polar Z-axis. © 2014, Pleiades Publishing, Ltd.

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