Oxygen Permeation Properties of Co-Free Perovskite-Type Oxide Membranes Based on BaFe[sub 1−y]Zr[sub y]O[sub 3−δ]

2009 ◽  
Vol 156 (5) ◽  
pp. E81 ◽  
Author(s):  
Ken Watanabe ◽  
Daisuke Takauchi ◽  
Masayoshi Yuasa ◽  
Tetsuya Kida ◽  
Kengo Shimanoe ◽  
...  
Keyword(s):  
Oxygen Permeation ◽  
Perovskite Type Oxide ◽  
Oxide Membranes ◽  
Perovskite Type ◽  
Permeation Properties

First-principles Studies of Phase Stability and the Neutral Atomic Vacancies in LiNbO3, NaNbO3 and KNbO3

2005 ◽  
Vol 902 ◽  
Author(s):  
Akio Shigemi ◽  
Takahiro Wada
Keyword(s):  
Enthalpy Of Formation ◽  
Density Functional ◽  
Formation Energy ◽  
Type Structure ◽  
Enthalpies Of Formation ◽  
Functional Formalism ◽  
Reducing Atmosphere ◽  
Perovskite Type Oxide ◽  
Formation Energies ◽  
Perovskite Type

AbstractWe overall evaluated the enthalpies of formation and the formation energies of neutral vacancies in ANbO3 (A = Li, Na, K) using a plane-wave pseudopotential method within a density functional formalism. The LiNbO3 phase with the LiNbO3-type structure was confirmed to have lower enthalpy of formation than that with perovskite- or ilmenite-type structure. The NaNbO3 (R3c) and KNbO3 (Bmm2 and R3m) phases with the lowest symmetry were found to have the lowest enthalpy of formation. The formation energy of a A vacancy was found to be the lowest under an oxidizing atmosphere and that of an O vacancy was found to be the lowest under a reducing atmosphere. The formation energy of a Nb vacancy was the highest under both oxygen-rich and -poor conditions. These results are in agreement with the empirical rule that B site defects in perovskite-type oxide do not exist.

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