Oxygen nonstoichiometry of La 1− xSr xCoO 3− δ (0 < x ≤ 0.6)

Abstract

The oxygen nonstoichiometry (δ) of La 1− x Sr x CoO 3− δ (0 < x ≤ 0.6) has been studied as a function of temperature (573–1673 K) and oxygen partial pressure (1–10 −3 atm) using TGA and coulometric titration techniques. The absolute values of oxygen nonstoichiometry were determined by the direct reduction in a flux of hydrogen (TGA) or by decreasing P O 2 in a coulometric titration cell. The boundaries of phase stability of La 0.7Sr 0.3CoO 3−δ and (La 0.7Sr 0.3) 2CoO 4± v were evaluated. A possible mechanism of disordering processes has been discussed.