HIGH-TEMPERATURE REDOX BEHAVIOUR OF DOUBLE PEROVSKITE Ba2CuWO6

The rock-salt ordered double perovskite Ba2CuWO6 phase was synthesized and unit cell parameters were calculated by the Rietveld method in the frameworks of tetragonal structure with I4/mmm space group. The equilibrium oxygen content was measured by TG in the air and the reducing atmosphere.The authors appreciate the support of this work within the government assignment № AAAA-A19-119110190048-7

Defect equilibrium in PrBaCo2O5+δ at elevated temperatures

A defect equilibrium model for PrBaCo2O5+δ is suggested based on oxygen non-stoichiometry data. The model includes reactions of oxygen exchange and charge disproportionation of Co3+ cations. The respective equilibrium constants, enthalpies and entropies for the reactions entering the model are obtained from the fitting of the experimental data for oxygen non-stoichiometry. The enthalpies of oxidation Co2+→ Co3+ and Co3+→Co4+ are found to be equal to 115±9 kJ mol-1 and 45±4 kJ mol-1, respectively. The obtained equilibrium constants were used in order to calculate variations in concentration of cobalt species with non-stoichiometry, temperature and oxygen pressure. © 2013 Elsevier Inc

The effect of processing conditions on the dielectric properties of doped calcium lanthanum nickelate

The influence of thermal and thermobaric (TBT) effects on the structure, microstructure, and dielectric properties of ceramics based on solid solutions of the La1.8Ca0.2Ni0.8M0.2O4+δ (M = Co, Cu) composition was studied. TBT treatment of the samples leads to a change in the grain morphology of ceramics and an increase in the dielectric constant compared to its value only after heat treatment. The change in the anisotropy of the coordination (La,Ca)O9 and (Ni,M)O6 polyhedra after TBT contributed to interlayer polarization in the crystal structure of La1.8Ca0.2Ni0.8M0.2O4+δ

SYNTHESIS FEATURES AND DETERMINATION OF OXYGEN CONTENT IN DOUBLE PEROVSKITE-LIKE MANGANITES OF COMPOSITION LnBaMn2O6-Δ (LN = Nd, Sm)

The complex oxides were synthesized by precursor combustion in 3 steps. The oxygen content and the value of the oxygen capacity were determined by a conjunction of teragravim-etry with coulometric and iodometric titration methods. The ordered manganites were found to possess highest oxygen capacity.Работа выполнена при финансовой поддержке РНФ №19-79-10147

AB Initio Estimations of Transport Properties of Solid Oxide Molybdates

This work is aimed at comprehensive theoretical study of Sr2MMoO6 molybdates with M = Ti, V, Cr, Mn, Fe, Co, Ni. It is shown that the experimentally observed variations of electronic conductivity in these compounds can be reasonably explained with the help of DFT calculations.Работа выполнена при поддержке Российского фонда фундаментальных исследований (РФФИ) в рамках проекта №19-79-10147

Influence of the Cationic Distribution of the B-Site of La(MnFeCoNiCu)O3-δ High-Entropy Oxides on the Crystal Structure and Properties

High-entropy perovskites La(MnFeCoNiCu)O3–δ are obtained via combustion of glyc-erol-nitrate precursors and consequent annealing at 1100 °C. Most of the samples are single-phase with different symmetric types within the perovskite-like crystal structure. The cationic distribution over sintered sample

Nonlinear optics and light localization in periodic photonic lattices

We review the recent developments in the field of photonic lattices emphasizing their unique properties for controlling linear and nonlinear propagation of light. We draw some important links between optical lattices and photonic crystals pointing towards practical applications in optical communications and computing, beam shaping, and bio-sensing.Comment: to appear in Journal of Nonlinear Optical Physics & Materials (JNOPM

INFLUENCE OF THE ADDITION OF ALKALI METAL FLUORIDES ON THE THERMOPHYSICAL PROPERTIES OF PHOSPHATE GLASSES

The thermophysical properties of phosphate and borophosphate glasses were studied. The effect of the FLiNaK additive on the glass transition temperature, crystallization activation energy and crystallization temperature was investigated

ION TRANSPORT IN HIGHLY NONSTOICHIOMETRIC OXIDES WITH PEROVSKITE-LIKE STRUCTURE

Solid solutions with nominal composition Pr1-xYxBaCo2-yAlyO6-δ where x = 0, 0.1 and y = 0, 0.1 were synthesized, phase purity of the samples obtained was confirmed by XRD analysis. Cobaltites’ equilibrium oxygen content was determined via combination of coulometric titration and thermogravimetry. Thermal expansion of Pr1-xYxBaCo2-yAlyO6-δ oxides was studied with the help of dilatometry. Oxygen permeability was measured in a specially equipped device. Theoretical model was proposed and used for explanation of the data obtained

MODELING AND STRUCTURAL CERTIFICATION OF COMPLEX OXIDE COMPOUNDS BASED ON La0.6Sr0.4Fe0.8Co0.2O

Calculations of the configuration entropy, fixation coefficients, and crystal structure of the perovskite type based on rare earths and 3d transition metals are performed. Calculations of the crystal structure of compounds are carried out using methods of the theory of the electron density functional.Работа выполнена при финансовой поддержке Российского Научного Фонда (проект № 23-23-00083)