Oxygen nonstoichiometry and electrical conductivity of the solid solutions La2−xSrxNiOy (0≤x≤0.5)

Abstract Oxygen nonstoichiometry and electrical resistance of a series La 2− x Sr x NiO y solid solutions, where x =0.0, 0.2 and 0.5 in argon flows at oxygen partial pressures 1.5, 10.2, 49.2, 100 and 286 Pa within the temperature range of 20–1050°C were studied. Nickelate oxygen desorption/sorption spectra when heating–cooling at constant rate demonstrated strong dependence of cation composition of the samples. Unlike La 1.5 Sr 0.5 NiO y compounds those of La 2 NiO y and La 1.8 Sr 0.2 NiO y have weakly bonded oxygen, capable to exchange reversibly with the gas phase at the temperatures higher than 250°C. The equilibrium values of oxygen nonstoichiometry and specific resistance for the these nickelates were determined at 300–1050°C and p O 2 =1.5–286 Pa as a functions of temperature versus oxygen partial pressure. All nickelate studied appear to be p-type conductors with metal electric conductivity at equilibrium states.