Intrinsic magnetic properties of BixCo2-xMnO4 spinels obtained by short-time etching

Autor(es)

dos Santos, M. E. ^{[1, 2]} ; Lisboa-Filho, P. N. ^[3] ; Gouttefangeas, F. ^[1] ; Pena, O. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Rennes, Inst Sci Chim Rennes, UMR 6226, F-135042 Rennes - France

^[2] Univ Estadual Paulista, Grp Mat Avancados, UNESP, BR-17033360 Baum, SP - Brazil

^[3] Univ Estadual Paulista, Dept Fis, Fac Ciencias, BR-17033360 Bauru, SP - Brazil

• Tipo de documento: Artigo de Revisão
• Fonte: Journal of Magnetism and Magnetic Materials; v. 339, p. 157-162, AUG 2013.
• Citações Web of Science: 2

Resumo

We report the structural and magnetic properties of Co2MnO4, partially substituted by Bi at the octahedral site. Bismuth enhances ferromagnetism due to a decrease of the Co2+-Co2+ antiferromagnetic interactions and an increase of the Ma(3+)-Mn4+ exchanges. Spurious phases (magnetic and/or nonmagnetic oxides) can easily form because of the large differences between the ionic radii of Bi3+ and Co3+, hiding or altering the intrinsic physical properties of the main BixCo2-xMnO4 phase. An easy way to eliminate the secondary phases is using acid reagents. Short-time etching of Bi0.1Co1.9MnO4 using nitric acid was successfully used, keeping most of the properties of the initial compound, with no alteration of the crystallographic structure. Final stoichiometry was respected (similar to Bi0.08Co1.82MnO4), meaning that the material after etching definitely contains bismuth elements in its structure and the observed properties are intrinsic to the oxide spinel. Additional experiments were performed as a function of the synthesis conditions, showing that an optimal pH value of 7 allowed the best magnetic response of the non-doped material. (C) 2013 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 07/08072-0 - Pesquisa fundamental em supercondutividade e magnetismo - sistemas com potencial para aplicações: óxidos avançados e supercondutores dotados de estruturas artificiais
• Beneficiário: Wilson Aires Ortiz
• Modalidade de apoio: Auxílio à Pesquisa - Temático