"The objective of this project is to obtain oxide materials of a new class based on yttrium with the general formula Y2-xBa3 + xFe3-yCo2 + yO15-d, attestation of the properties of the obtained materials and their practical application.
As a result, optimal synthesis techniques will be determined, including annealing temperature, annealing time for new layered perovskites. The crystal structure and structural parameters of the obtained oxides will be determined by X-ray diffraction analysis (XRD) and refined by the Rietveld method of full-profile analysis. Oxygen non-stoichiometry of oxide materials will be investigated as a function of temperature (T) and oxygen partial pressure (pO2) by thermogravimetric analysis (TGA) and coulometric titration. A model analysis of the defect structure of the oxide phases will be performed and the most adequate models are established based on the data on oxygen non-stoichiometry.
Measurements of the electrical conductivity of oxide materials will be performed using a 4-contact DC method, depending on T and pO2. Thermal expation of these materials will be determined depending on T and pO2 simultaneously with the general electrical conductivity. Analysis of the electrotransport properties and data on the defective structure will allow to determine the most important transport characteristics of ion and electronic charge carriers, such as mobility, the numbers and the activation energy of transport, and the diffusion coefficients. The coefficients of thermal expansion of the samples Y2-xBa3 + xFe3-yCo2 + yO15-d will be calculated and the isobaric dependences of the relative elongation of the samples on temperature are obtained. Chemical and thermal compatibility with popular materials used as electrolytes is established."