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Titolo:
Defect chemistry modelling of oxygen-stoichiometry, vacancy concentrations, and conductivity of (La1-xSrx)(y)MnO3 +/-delta
Autore:
Poulsen, FW;
Indirizzi:
Riso Natl Lab, Dept Mat Res, DK-4000 Roskilde, Denmark Riso Natl Lab Roskilde Denmark DK-4000 at Res, DK-4000 Roskilde, Denmark
Titolo Testata:
SOLID STATE IONICS
fascicolo: 1-4, volume: 129, anno: 2000,
pagine: 145 - 162
SICI:
0167-2738(200004)129:1-4<145:DCMOOV>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
OXIDATION-REDUCTION BEHAVIOR; YTTRIA-STABILIZED ZIRCONIA; SR-DOPED LAMNO3; LANTHANUM MANGANITE; INTERFACE REGIONS; LAMNO3+/-DELTA; EXCHANGE; NONSTOICHIOMETRY; PEROVSKITES; EQUILIBRIA;
Keywords:
conductivity; defect modelling; LSM; non stoichiometry; perovskite; sequential algorithm;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
--discip_EC--
Citazioni:
48
Recensione:
Indirizzi per estratti:
Indirizzo: Poulsen, FW Riso Natl Lab, Dept Mat Res, DK-4000 Roskilde, Denmark Riso Natl Lab Roskilde Denmark DK-4000 000 Roskilde, Denmark
Citazione:
F.W. Poulsen, "Defect chemistry modelling of oxygen-stoichiometry, vacancy concentrations, and conductivity of (La1-xSrx)(y)MnO3 +/-delta", SOL ST ION, 129(1-4), 2000, pp. 145-162

Abstract

Two precise algorithms are devised for the calculation of defect concentrations in A-site acceptor doped ABO(3) perovskites. The two models contain nine species including cation vacancies on the A- and B-site. The small polaron model is based on three redox levels of the B-ion. A large polaron model, based on delocalised electrons, electron holes and all B-ions being trivalent is given in Appendix A. The sequential mathematical method allows us to calculate the high temperature oxygen partial pressure dependent properties of (La1-xSrx)(y)MnO3+/-delta in a unified manner irrespective of the type of defect regime, Simulations are shown for a pO(2) span from 10(-30) to10(5) atm. The three required equilibrium constants for (La1-xSrx)(y)MnO3+/-delta had to be changed significantly from values given in literature in order to match the observed stoichiometry span. The main results shown are calculated by the small polaron model containing only ionic species - the B-ion may be Mn-B' (Mn2+), Mn-B(x) (Mn3+), and Mn-B(Mn4+). The A/B-ratio = ygreatly influences the oxygen stoichiometry, oxygen ion vacancy- and cation vacancy concentrations and the total conductivity. Calculations are givenfor the range 0.87 less than or equal to y less than or equal to 1.13 for a Sr doping of 10% at 1000 degrees C. The defect model can simultaneously describe the observed stoichiometry and conductivity dependence on pO(2), ifthe electronic mobility is decreased by up to 50% at pO(2) < 10(-10) and pO(2) > 10(-2) arm. (C) 2000 Elsevier Science B.V. All rights reserved.

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Documento generato il 30/09/20 alle ore 12:45:38