Oxygen nonstoichiometry and some transport properties of LaSrNiO sub(4- delta ) nickelate

Oxygen nonstoichiometry and electrical conductivity of LaSrNiO sub(4- delta ) nickelate were investigated and oxygen permeability of LaSrNiO sub(4- delta )+40% Ag composite ceramics was estimated. The oxygen content in LaSrNiO sub(4- delta ) changes from 3.99 to 3.45 in the temperature range 600-1000 degree C at oxygen partial pressures 100 to 2 Pa. The decrease of oxygen content in nickelate takes place by removing it from vertexes of NiO sub(6) octahedrons which form the perovskite layers within the lattice of nickelate. This causes an increase of the c parameter and a decrease of the a parameter of the tetragonal cell of nickelate. The cell volume of the crystal remains constant. The nickelate studied appeared to be p-type conductor with a metallic-like temperature function of the electrical conductivity. At the same experimental conditions the oxygen permeability of LaSrNiO sub(4- delta )+40% Ag composite is lower by a factor of 100 in comparison with the permeability of La sub(2)NiO sub(4 plus or minus delta ) and La sub(2)NiO sub(4 plus or minus delta )+40% Ag composite.