Nonstoichiometry of the perovskite-type oxides La1−xSrxCoO3−δ

Structural phenomena associated with the spin-state transition inLaCoO3

“…Misuzaki et al 23 have determined the following expressions for the enthalpy and entropy of oxygen vacancy formation: (Table IV). For small B site cations, the structure is rhombohedral (space group c R3 ), and a transition to the orthorhombic space group Pnma occurs for r B ~ 0.6.…”

High-Temperature Coulometric Titration of La1−xSrxCoO3−δ: Evidence for the Effect of Electronic Band Structure on Nonstoichiometry Behavior

“…From this reaction it is seen that pumping oxygen into the oxide lattice leads to changes in both the lattice oxygen vacancy and the itinerant electron concentration. The equilibrium condition for reaction [4] is given by…”

Oxygen permeation modelling of perovskites

“…The oxygen nonstoichiometry of La~_ySryCrO3, Lal_ySryFeO3 and Lal_ySryCoO3 can all be described with the same point defect model [11][12][13][14] when the Sr content is small. Lal_ySryMnO3 behaves slightly different.…”

“…1, experimental data of the nonstoichiometry of the Lao.7sSro.2sCrO3, Lao.9Sro.lFeO3, Lao.9Sro.tCoO3 and Lao.sSro.2MnO3 perovskites [11][12][13][14][15] are compared with the nonstoichiometry calculated from the model parameters given in table 1. Close agreements are seen between the experimentally determined and calculated nonstoichiometry for the Cr, Mn, Fe and Co-perovskites.…”

“…In this case, the oxygen partial pressure dependence of their ionic conductivity should be known. Assuming a vacancy diffusion mechanism, the ionic conductivity can be calculated form data of oxygen nonstoichiometry [11][12][13][14][15] and vacancy diffusion coefficients [ 16,17 ]. This gives a new analytical expression which describes the oxygen permeation current density as a function of the oxygen partial pressure gradient.…”