resumo
Changes in nominal composition of the perovskite (ABO(3)) solid solution Ba1-x(Zr,Pr)O3-delta and adjusted firing conditions at very high temperatures were used to induce structural changes involving site redistribution and frozen-in point defects, as revealed by Raman and photoluminescence spectroscopies. Complementary magnetic measurements allowed quantification of the reduced content of Pr. Weak dependence of oxygen stoichiometry with temperature was obtained by coulometric titration at temperatures below 1000 degrees C, consistent with a somewhat complex partial frozen-in defect chemistry. Electrical conductivity measurements combined with transport number and Seebeck coefficient measurements showed prevailing electronic transport and also indicated trends expected for partial frozen-in conditions. Nominal Ba deficiency and controlled firing at very high temperatures allows adjustment of structure and partial frozen-in defect chemistry, opening the way to engineer relevant properties for high-temperature electrochemical applications.
palavras-chave
DOPED BAPRO3; OXYGEN NONSTOICHIOMETRY; TRANSPORT-PROPERTIES; RAMAN-SCATTERING; CERAMICS; BATIO3; CONDUCTIVITY; STABILITY; OXIDE; MECHANOSYNTHESIS
categoria
Chemistry
autores
Antunes, I; Milchalev, S; Mather, GC; Kharton, VV; Figueiras, FG; Alves, A; Rodrigues, J; Correia, MR; Frade, JR; Fagg, DP
nossos autores
Fábio Gabriel Nazário Figueiras
Bolseiro de pós-Doutoramento
Isabel Alexandra Gonçalves Antunes
Investigador Júnior
Jorge Ribeiro Frade
Professor(a) Jubilado(a)
Vladislav Kharton
Investigador Principal Covidadoagradecimentos
This work was supported by the FCT, Portugal (grants SFRH/BD/76738/2011, SFRH/BPD/80663/2011, IF/01344/2014), FCT, COMPETE and FEDER (project number EXPL/EMS-ENE/1497/2013), MINECO, Spain (ENE2012-30929), and CSIC, Spain (i-link0743).