Crystal structure and imperfection of the perovskite-like proton conductor Ba4Ca2Nb2O11

The crystal structure complex oxide Ba4Ca2Nb2O11 in anhydrous and hydrated forms was studied by the method of neutron diffraction, the preferred localizations of protons were set. The hydration process with temperature variation and the partial pressure of water vapor was studied. It is established that the crystallographic non-equivalence of OH-groups in the structure determines their different thermal stability. The quasi-chemical approach was proposed that describes the formation of proton defects in oxides with structural disordering

Electrical properties of Ba2(In1-x Al x )2O5 solid solutions

The electric conductivity of perovskite-like Ba2(In 1-x Al x )2O5 solid solutions (0 < x ≤ 0.20) characterized by structural disordering in the oxygen sublattice was studied as a function of temperature and partial pressure of oxygen in an atmosphere with a low content of water vapors (pH2O = 3 Ч 10-5 atm). When In3+ was partially replaced by Al3+, the oxygen ion conductivity increased because of the disordering of oxygen structural vacancies, leading to a significant increase in the total electric conductivity of the samples. © 2013 Pleiades Publishing, Ltd

Electrical Properties of (1–x)La2Mo2O9-xLa2Mo3O12 (x = 0.15) Composite System

Electrical properties of (1–x)La2Mo2O9 –xLa2Mo3O12 (x = 0.15) composite system areinvestigated. Introduction of an inert additional phase La2Mo3O12 (adjacent phase to La2Mo2O9 in the phase diagram) results in an increase in conductivity of composite by approximately one order of magnitude. This increase is associated with the appearance of a composite effect. The dominant ionic conductivity is maintained in the wide range of oxygen partial pressures. The calculated ion transport numbers are close to 1. Keywords: lanthanum molybdate, LAMOX, heterogeneous doping, composites, oxide–ion conductivit

The Effect of Simultaneous Homo- and Heterogeneous Doping on Transport Properties of Ba2In2O5

In this article, the possibility of application of simultaneous homogeneous and heterogeneous doping has been described for the first time. The composite 0.7Ba1.95In2O4.9F0.1⋅0.3Ba2 InNbO6 has been obtained by in situ solid-state method. The scanning electron microscopy and thermogravimetry investigations have beencarried out; the electrical properties have been examined. It has been proved that simultaneous homogeneous and heterogeneous doping is a prospective method for obtaining high-conductive proton electrolytes. Keywords: brownmillerite, composite, anionic doping, fluorin

The effect of heterogeneous doping on transport properties of lanthanum dimolybdate

A heterogeneous doping method was used for the first time to modify the transport properties of the oxygen-ion conductor La(2)Mo(2)O(9). The effect of temperature and oxygen partial pressure in the gas phase on conductivity of the obtained composite {0.85La2Mo2O9–0.15La2Mo3O12} was studied. Introduction of 15 mol. % an inert low-conductive additional phase La(2)Mo(3)O(12) results in an increase in conductivity of the matrix phase by nearly 1 orders of magnitude. It is associated with appearance of a composite effect. However, there is no suppression of the α-La(2)Mo(2)O(9)↔β-La(2) Mo(2)O(9) phase transition. It is shown that the conductivity type of both lanthanum dimolybdate and composite based on it is predominantly ionic in the wide range of oxygen partial pressures. © Siberian Federal University. All rights reserve

Phase Composition and Electrical Properties of Samples Based on Si-Doped Barium Indate and Barium Silicate

Исследованы фазовый состав и электрические свойства образцов в системе на основе допированного кремнием индата бария и силиката бария. Настоящая работа представляет собой пример одновременного гомогенного и гетерогенного допирования как способ улучшения свойств твердых электролитов, в частности, кислород-ионного и протонного проводника Ba2In2O5. Образцы в системе (1-x)Ba2In1.8Si0.2O5.1 ⋅ xBa2SiO4 (х = 0.0, 0.1, 1.0) были получены твердофазным методом. Данными рентгенофазового анализа подтвержден их фазовый состав: образец с x=0.1 представляет собой композит, содержащий твёрдый раствор на основе индата бария и ортосиликат бария. Исследованы электрические свойства образцов, обработанных при температуре 1300 ºС. Показано, что существенного изменения проводимости твердого раствора при введении фазы силиката бария не наблюдается, при этом относительная плотность композиционной керамики увеличивается с 80 до 90 %.The phase composition and electrical properties of samples in the system based on silicon-doped barium indate and barium silicate were investigated. The present work is an example of simultaneous homogeneous and heterogeneous doping as a way to improve the properties of solid electrolytes, in particular oxygen-ion and proton conductor. The samples in the system (1-x)Ba2In1.8Si0.2O5.1 ⋅ xBa2SiO4(х = 0.0, 0.1, 1.0) were obtained by solid-phase method. The data of X-ray phase analysis confirmed their phase composition: the sample with x=0.1 represent a composite containing a solid solution based on barium indate and barium orthosilicate. The electrical properties of the samples treated at 1300 ºC were investigated. It is shown that there is no significant change in the conductivity of the solid solution with the introduction of barium silicate phase, while the relative density of the composite ceramics increases from 80 to 90%.Работа выполнена при поддержке госзадания АААА-А20-120061990010-7

Improvement of Transport Properties of Oxygen-ion Conductor La2Mo2O9 BY Heterogeneous Doping Method

The composite sample based on oxygen-ion conductor La2Mo2O9 and heterogeneous dopant La2MoO6 was prepared. Its electrical properties wereinvestigated. It was found that the composite is an oxygen-ionic conductor and has improved electrical conductivity compared to the initial phases.Получен композиционный образец на основе кислородноионного проводника La2Mo2O9 и гетерогенной добавки La2MoO6. Исследованы его электрические свойства. Выяснено, что композит является кислородноионным проводником и обладает улучшенной электропроводностью по сравнению с индивидуальными фазами

PROPERTIES OF COMPOSITES BASED ON Ba2In2O5–Ba2InMO6 (M=Nb, Ta) SYSTEMS DEPENDING ON THE PREPARATION METHOD

Composites based on the Ba2In2O5–Ba2InMO6 (M=Nb, Ta) systems were prepared by mechanical mixture method from initial components previously synthesized in various ways (by using solution and solid-phase technologies). It was found that the morphology of initial components can influence on electrical

COMPOSITE ELECTROLYTES BASED ON BARIUM INDATE AS FUNCTIONAL MATERIALS FOR A WATER VAPOUR SENSOR

The 2 2 5 2 6 (1 x)Ba In O xBa InNbO (x=0.2, 0.3) composite electrolytes with proton conductivity were studied as functional materials for a watervapoursensor. It was found the electrolytes may be used only in narrow temperature-range 400-450oC.Работа выполнена при финансовой поддержке РФФИ (проект № 16-33-00285 мол_а)

Results of observations of asteroids at the Russian–Turkish RTT-150 telescope from 2004–2013

© 2015, Allerton Press, Inc. We report the results of analysis of the data volume containing 13834 topocentric positions of 231 asteroids obtained from observations at the Russian–Turkish RTT-150 telescope (TÜBITAK (Scientific and Technological Research Council of Turkey), Turkey) in 2004–2013. The positions of asteroids were calculated with the differential reduction method in the ICRS system with the use of the reference catalogs of the UCAC series. The observational program covered the main-belt asteroids closely encountering the other asteroids and the near-Earth asteroids (NEA). For the main belt asteroids, the mean-square error of one position was 84 and 68 mas in right ascension and declination, respectively, while it was 160 and 120 mas, respectively, for NEAs. The obtained volume of the asteroid positions widens the arc of groundbased observations of these bodies, which is important for evaluating their orbital elements with a higher accuracy. Moreover, observations of the main-belt asteroids in the periods of close encounters yield valuable material to solve the problem on accurate estimation of the masses of asteroids with a dynamic method. It has been shown that the supplementing of the input dataset with the here-reported observational volume decreases the error in the estimates of the perturbing asteroid mass and the orbital parameters of perturbed bodies