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Titolo: Defect chemistry modelling of oxygenstoichiometry, vacancy concentrations, and conductivity of (La1xSrx)(y)MnO3 +/delta
Autore: Poulsen, FW;
 Indirizzi:
 Riso Natl Lab, Dept Mat Res, DK4000 Roskilde, Denmark Riso Natl Lab Roskilde Denmark DK4000 at Res, DK4000 Roskilde, Denmark
 Titolo Testata:
 SOLID STATE IONICS
fascicolo: 14,
volume: 129,
anno: 2000,
pagine: 145  162
 SICI:
 01672738(200004)129:14<145:DCMOOV>2.0.ZU;2I
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 OXIDATIONREDUCTION BEHAVIOR; YTTRIASTABILIZED ZIRCONIA; SRDOPED 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, DK4000 Roskilde, Denmark Riso Natl Lab Roskilde Denmark DK4000 000 Roskilde, Denmark



 Citazione:
 F.W. Poulsen, "Defect chemistry modelling of oxygenstoichiometry, vacancy concentrations, and conductivity of (La1xSrx)(y)MnO3 +/delta", SOL ST ION, 129(14), 2000, pp. 145162
Abstract
Two precise algorithms are devised for the calculation of defect concentrations in Asite acceptor doped ABO(3) perovskites. The two models contain nine species including cation vacancies on the A and Bsite. The small polaron model is based on three redox levels of the Bion. A large polaron model, based on delocalised electrons, electron holes and all Bions being trivalent is given in Appendix A. The sequential mathematical method allows us to calculate the high temperature oxygen partial pressure dependent properties of (La1xSrx)(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 (La1xSrx)(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 Bion may be MnB' (Mn2+), MnB(x) (Mn3+), and MnB(Mn4+). The A/Bratio = 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