Phase and structural study of self-doped La1-x-yCaxOyMnO3+delta

• Tipo: Artigo em Revista Científica Internacional
• Data: 2004

Autores

Figueiras, F. G. (Autor) Outra; Araújo, João Pedro (Autor) FCUP; Amaral, V. S. (Autor) Outra; Tavares, Pedro B. (Autor) Outra; Lopes, A. L. B. (Autor) Outra; Vieira, Joaquim Manuel (Autor) Outra

Revista

Título: Acta Physica Polonica A

Vol. 105

Páginas: 173-182

ISSN: 0587-4246

Editora: POLSKA AKADEMIA NAUK

Indexação

ISI Web of Knowledge - 1 Citação

Scopus - 1 Citação

Outras Informações

ID Authenticus: P-000-C09

DOI: 10.12693/aphyspola.105.173

Abstract (EN): To understand the combined effect of divalent ion and A-site vacancy (circle divide) self-doping, beyond the binary La1-xMnO3 system, polycrystalline La(1-x-y)Ca(x)circle divide(y)MnO(3+delta) samples were studied. Samples with Ca substitution and excess Mn in the range x < 0.33 and y < 0.45, respectively, were prepared by standard solid-state reactions. Structural and phase analysis of the samples were done by X-ray diffraction and transmission electron microscopy. The manganite structure in this composition range includes rhombic and orthorhombic phases. Most samples contain the hausmanite phase (Mn3O4) coexisting with the manganite phase. A small amount of perovskite related AMn(7)O(12) (A = La, Ca) structure near the hausmanite-manganite boundary is also found in samples treated in oxygen atmosphere. The calculated vacancy content accommodated in the manganite phase can be higher than 1/8, the reported limit for La1-xMnO3, which is confirmed in our x = 0 sample. For the compositions studied, a ferromagnetic metallic behavior below T-C is found, confirming the stability of the Mn sublattice, and near the optimum stoichiometric ((x = 0.33, y = 0) system, a net A-site vacancy content (up to y = 0.2) does not degrade the magnetic and electric properties.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 10