resumo
A new oxide of the Ruddlesden-Popper series has been isolated and structurally characterized in the Eu-Sr-Co-Mn-O system. X-ray diffraction and electron microscopy show that polycrystalline Eu2SrCo1.5Mn0.5O7 constitutes the n = 2 member of a homologous series, the essential feature of which is the existence of two connected Co/Mn octahedral layers, separated by Eu atoms. Electrochemical studies show that the area-specific resistance of this compound is 0.15 Omega cm(2) at 700 degrees C in air, a performance which is comparable to that of the best state-of-the-art materials used as cathodes in intermediate temperature solid oxide fuel cells. Below 150 K the title material presents two different magnetic phenomena. The first one corresponds to the formation of ferromagnetic nanoclusters (T-C similar to 121 K) within an ordered Co2+/Mn4+ atomic configuration, whereas at lower temperature (similar to 21 K) a spin glass state occurs.
palavras-chave
OXIDE FUEL-CELLS; COMPLEX MAGNETIC-BEHAVIOR; MN/CO ATOMIC ORDER; ELECTRICAL-CONDUCTIVITY; K2NIF4-TYPE STRUCTURE; THERMAL-EXPANSION; CRYSTAL-STRUCTURE; SOLID-SOLUTION; TEMPERATURE; CATHODES
categoria
Chemistry; Energy & Fuels; Materials Science
autores
Boulahya, K; Hassan, M; Gil, DM; Romero, J; Herrero, AG; Martin, SG; Amador, U
nossos autores
Daniel Muñoz Gil
Bolseiro de pós-Doutoramentoagradecimentos
We thank the Ministerio de Economia y Competitividad (MINECO) and Comunidad de Madrid for funding the projects MAT2013-46452-C4-1 R and MAT2013-46452-C4-4 R, and S2013/MIT-2753, respectively.