http://dspace.bstu.ru/jspui/handle/123456789/1846 Химия, химическая технология и композиты специального назначения Sun, 05 Apr 2026 17:12:47 GMT 2026-04-05T17:12:47Z http://dspace.bstu.ru/jspui/handle/123456789/2600 Title: On Enhancing the Thermal Stability of Metal Hydrides by Ion–Plasma Vacuum Magnetron Sputtering Authors: Pavlenko, V. I.; Cherkashina, N. I.; Yastrebinsky, R. N.; Demchenko, O. V. Abstract: The method of titanium-hydride pellet (THP) modification by the surface deposition of metal titanium with the ion–plasma vacuum magnetron sputtering is described in this paper. The surface microstructure of the initial samples is compared with that of samples with the deposited coating. Found to be practically the same along the surface, the thickness of the deposited layer equals approximately 275 nm. The interface between the deposited titanium and THP is visible over the entire recorded region. The spectra of the thermal desorption of hydrogen from the initial and titanium-coated samples are presented. The coating is shown to significantly increase the temperature of THP dissociation. Description: On Enhancing the Thermal Stability of Metal Hydrides by Ion–Plasma Vacuum Magnetron Sputtering / V. I. Pavlenko [et al.] // Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques. - 2017. - Vol. 11, No. 1. - P. 254–258. Mon, 01 Jan 2018 00:00:00 GMT http://dspace.bstu.ru/jspui/handle/123456789/2600 2018-01-01T00:00:00Z http://dspace.bstu.ru/jspui/handle/123456789/2599 Title: Electric field effect on variable-range hopping conductivity in Bi1.9Lu0.1Te3 Authors: Ivanova, O.; Yaprintsev, M.; Danshina, E. Abstract: Electric field effect on low-temperature electrical resistivity of n-type Bi1.9Lu0.1Te3 was examined and analyzed. It was found that with decreasing temperature from 35 down to 2.5 K, the conductivity mechanism changes from “metal” type to “semiconductor” one resulting in appearance of minimum in the specific electrical resistivity, ρ. The temperature of this minimum, Tm, depends on electric field strength, E. At low electric field of 0.15 Vˑm−1 this temperature is equal to∼11 K and decreases as E increases up to 4.65 Vˑm−1. Variable-range hopping (VRH) conductivity mechanism was applied to explain the ρ(T, E) behavior below Tm. Average hopping distance estimated from the experimental ρ(T, E) dependences decreases as temperature or electric field strength increase, that is the VRH conductivity can be activated both temperature and electric field. It was also found that density of states at the Fermi level rapidly enhances as electric field increases. This enhancement could be attributed to high and sharp density of states within an impurity band formed from the electronic f-levels of Lu. The forming of this impurity band is believed to be responsible for enhancement of the thermoelectric figure-of-merit of Bi2Te3. Description: Ivanova O. Electric field effect on variable-range hopping conductivity in Bi1.9Lu0.1Te3 / O. Ivanova, M. Yaprintsev, E. Danshina // Physica B: Condensed Matter. - 2018. - Vol. 545. - P. 222–227. Mon, 01 Jan 2018 00:00:00 GMT http://dspace.bstu.ru/jspui/handle/123456789/2599 2018-01-01T00:00:00Z http://dspace.bstu.ru/jspui/handle/123456789/2598 Title: Peculiarities of the dielectric properties of ternary 0.5(Y0.1Zr0.9O2) –0.5(0.6SrTiO3 – 0.4BiScO3) ceramic system Authors: Ivanov, O.; Danshina, Е. Abstract: Ceramic samples of ternary 0.5(Y0.1Zr0.9O2) – 0.5(0.6SrTiO3 – 0.4BiScO3) system consisting of individual Y0.1Zr0.9O2 and 0.6SrTiO3 – 0.4BiScO3 subsystems were synthesized via solid-state processing techniques. By XRD analysis, a coexistence of tetragonal P42/nmc phase related to the Y0.1Zr0.9O2 subsystem, and cubic Pm3m and tetragonal P4mm phases associated with the 0.6SrTiO3 – 0.4BiScO3 subsystem was found. A deviation of real composition from nominal one for both Y0.1Zr0.9O2 and SrTiO3 – BiScO3 subsystems due to Sc substituting for Zr in the Y0.1Zr0.9O2 subsystem and, vice versa, Zr substituting for Sc in the SrTiO3 – BiScO3 subsystem was also observed. Peculiarities of the dielectric properties related to both diffuse ferroelectric phase transition and dielectric relaxation processes were found and analyzed in comparison with the dielectric properties of twocomponent 0.6SrTiO3 – 0.4BiScO3 system. It was found that the diffuse phase transition in ternary system, firstly, shifts to lower temperatures and, secondly, has a less degree of diffuseness as compared to two-component system. Such kind of behavior could be attributed to a difference of ionic radii of ions Zr4+ and Sc3+. Dielectric relaxation processes associated with the O2- ions migration were observed within temperature 500–800 K for both ternary and two-component systems. Two dielectric relaxation processes related to the Y0.1Zr0.9O2 and 0.6SrTiO3 – 0.4BiScO3 subsystems were found in ternary system, whereas one dielectric relaxation process was observed in two-component system. The activation energies for the dielectric relaxation processes were estimated as ~1.3 eV and ~0.9 eV for Y0.1Zr0.9O2 and 0.6SrTiO3 – 0.4BiScO3 subsystems, respectively, for ternary system, and ~0.75 eV for two-component system. Description: Ivanov O. Peculiarities of the dielectric properties of ternary 0.5(Y0.1Zr0.9O2) –0.5(0.6SrTiO3 – 0.4BiScO3) ceramic system / O. Ivanov, E. Danshina // Ceramics International. - 2018. - Vol. 44. - P. 22856–22864. Mon, 01 Jan 2018 00:00:00 GMT http://dspace.bstu.ru/jspui/handle/123456789/2598 2018-01-01T00:00:00Z http://dspace.bstu.ru/jspui/handle/123456789/2597 Title: Anisotropic thermoelectric properties of Bi1.9Lu0.1Te2.7Se0.3 textured via spark plasma sintering Authors: Vasil'ev, A.; Yaprintsev, M.; Ivanov, O.; Danshina, E. Abstract: Spark plasma sintering method was applied to prepare bulk n-type Bi1.9Lu0.1Te2.7Se0.3 samples highly textured along the 001 direction parallel to the pressing direction. The texture development is confirmed by X-ray diffraction analysis and scanning electron microscopy. The grains in the textured samples form ordered lamellar structure and lamellar sheets lie in plane perpendicular to the pressing direction. The average grain size measured along the pressing direction is much less as compared to the average grain size measured in the perpendicular direction (∼50 nm against ∼400 nm). A strong anisotropy in the transport properties measured along directions parallel and perpendicular to the pressing direction within the 290 ÷ 650 K interval was found. The specific electrical resistivity increases and the thermal conductivity decreases for the parallel orientation as compared to these properties for the perpendicular orientation. The Seebeck coefficient for both orientations is almost equal. Increase of the electrical resistivity is stronger than decrease of the thermal conductivity resulting in almost three-fold enhancement of the thermoelectric figure-of-merit coefficient for the perpendicular orientation (∼0.68 against ∼0.24 at ∼420 K). The texturing effect can be attributed to (i) recovery of crystal structure anisotropy typical for the single crystal Bi2Te3-based alloys and (ii) grain boundary scattering of electrons and phonons. An onset of intrinsic conductivity observed above Td≈410 K results in appearance of maxima in the temperature dependences of the specific electrical resistivity, the Seebeck coefficient and the thermoelectric figure-of-merit coefficient and minimum in the temperature dependence of the total thermal conductivity. The intrinsic conductivity is harmful for the thermoelectric efficiency enhancement since thermal excitation of the electron-hole pairs reduces the Seebeck coefficient and increases the thermal conductivity. Description: Anisotropic thermoelectric properties of Bi1.9Lu0.1Te2.7Se0.3 textured via spark plasma sintering / A. Vasil'ev [et al.] // Solid State Sciences. - 2018. - Vol. 84. - P. 28–43. Mon, 01 Jan 2018 00:00:00 GMT http://dspace.bstu.ru/jspui/handle/123456789/2597 2018-01-01T00:00:00Z