A. Yu. Zuev

Crystal and defect structure of the mixed oxides LaMn1−zCuzO3±y (0≤z≤0.4)

Abstract The crystal structure and nonstoichiometry of the mixed Cu-doped lanthanum manganates LaMn1−zCuzO3±y (0≤z≤0.4) have been investigated by powder X-ray diffraction (PXD) and powder neutron diffraction (PND). The samples quenched in air from 1173 K to room temperature were crystallized in the orthorhombic structure (space group Pbnm). The oxygen positions, interatomic distances and occupancies have been refined based on the PXD and PND data. According to the refinement, mixed oxides LaMn1−zCuzO3±y with 0≤z≤0.2 exhibit full occupancies of the oxygen sites (O1 and O2) and deficiency of the La-sites. Oxygen nonstoichiometry in LaMn1−zCuzO3±y samples with values of z ranging from 0 to 0.3 were studied as a function of temperature (1150–1450 K) and oxygen partial pressure (10−3.5–1 atm) by means of thermogravimetry (TG). The absolute values of the oxygen nonstoichiometry (y) were determined by a full reduction in hydrogen and iodometric titration. A defect model describing experimental data is discussed.

The phase diagram of the bismuth-calcium oxide system

Abstract The phase relations in the Bi2O3-CaO system have been reexamined in air at temperatures over 740°C. Other than discovery of a new δ-phase (hexagonal structure), the phases present are in agreement with previous work, but the homogeneity ranges and high temperature relationships are in some cases at variance. A modified phase diagram is proposed.

The Bi2O3-SrO phase diagram

The phase relations in the Bi2O3-SrO system have been examined in air at temperatures above 740 °C. Intermediate phases were found to agree with previous work, but the homogeneity ranges and high-temperature phase relationships were in some cases at variance. A modified phase diagram is proposed.

The diffusion of oxygen and ion transport in lanthanum cobaltite LaCoO3-δ

AbstractThe chemical diffusion coefficient of oxygen vacancies and oxygen ion conductivity in lanthanum cobaltite LaCoO3 were determined by the polarization method as functions of oxygen partial pressure

Oxygen nonstoichiometry of lanthanum strontium cuprates La2−xSrxCuO4−δ

p_{O_2 }

Defects in doped perovskite-like lanthanum cobaltite crystals La1−xSrxCo1−yMeyO3−δ (Me = Cu and Mn)

(atm) and temperature T(K) over the ranges −4 ≤ log

Oxygen nonstoichiometry and defect structure of the double perovskite GdBaCo2O6 − δ

p_{O_2 }