Artigo
Effect of Eu substitution on the crystallographic and magnetic properties of the BiMn2O5 oxide obtained by urea combustion
Registro en:
Ceramics International. Oxford: Elsevier Sci Ltd, v. 40, n. 8, p. 13643-13648, 2014.
0272-8842
10.1016/j.ceramint.2014.05.091
WOS:000340321300130
1353862414532005
0000-0002-7734-4069
Autor
Ferreira, Rafael A. [UNESP]
Santos, Maria Elenice dos [UNESP]
Morilla-Santos, Cassio
Lebullenger, Ronan
Pena, Octavio
Lisboa-Filho, Paulo Noronha [UNESP]
Resumen
Polycrystalline oxide materials with nominal compositions BiMn2O5 and Bi0.9Eu0.1Mn2O5 were obtained by urea combustion. Crystallographic studies using X-ray diffraction and Rietveld Refinement techniques showed the formation of single-phase samples for both compositions, crystallizing in a mullite-type orthorhombic perovskite structure, space group Pbam (Z=4). Replacement of Bi+3 by Eu+3 promoted a slight distortion and a unit cell contraction due to a decrease of the c-parameter for Bi0.9Eu0.1Mn2O5. The SEM/EDX techniques confirmed the formation of single-phase materials with excellent mapping distribution. Magnetic measurements showed different behaviors: BiMn2O5 is an antiferromagnet (AFM) with a Neel temperature (T-N) of 41 K and a Curie-Weiss temperature Theta(CW) of -277 K, while Bi0.9Eu0.1Mn2O5 displayed a ferrimagnetic behavior with a T-C of 44K and Theta(CW) of 270 K. The role of Eu+3 and the mechanisms responsible for the magnetic transition are discussed on the basis of chemical bonds and exchange interactions. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) UNESP Univ Estadual Paulista, POSMAT Programa Posgrad Ciencia & Tecnol Mat, Bauru, SP, Brazil Univ Rennes 1, Inst Sci Chim Rennes UMR 6226, F-35014 Rennes, France Inst Tecnol Desenvolvimento LACTEC, Curitiba, Parana, Brazil UNESP Univ Estadual Paulista, Dept Fis, Fac Ciencias, Bauru, SP, Brazil UNESP Univ Estadual Paulista, POSMAT Programa Posgrad Ciencia & Tecnol Mat, Bauru, SP, Brazil UNESP Univ Estadual Paulista, Dept Fis, Fac Ciencias, Bauru, SP, Brazil FAPESP: 07/08072-0 FAPESP: 13/07296-2 CAPES: 706/11