Cation distribution and magnetic characterization of the multiferroic cobalt manganese Co2MnO4 spinel doped with bismuth
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2013-03-01
Autores
Dos Santos, Maria Elenice [UNESP]
Aparecido Ferreira, Rafael [UNESP]
Lisboa Filho, Paulo Noronha [UNESP]
Peña, Octavio
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Resumo
The structural and magnetic properties of the cubic spinel oxide Co 2MnO4 (Fd3m space group) doped with different concentrations of bismuth, were investigated by X-ray diffraction and SQUID magnetometry. The Bi3+ ions entering into the CoIII octahedral sites do not alter the effective moment, μeff ∼8.2 μB, whereas both the magnetization M50 kOe at the highest field (50 kOe) and the field-cooled MFC magnetizations increased when increasing the Bi content. The ferrimagnetic character of the parent compound, Co2MnO4, is maintained for all materials although the antiferromagnetic interactions Co2+-Co2+ are affected, resulting in higher values of the Curie-Weiss temperature. Due to the large ionic radius of Bi, octahedra distortions occur as well as valence fluctuations of the Mn ions, giving rise to Jahn-Teller effects and enhancing the exchange interactions. The off-center Bi3+ ion is responsible of non-centrosymmetric charge ordering and should lead to multiferroïsme conditions for the BixCo2-xMnO4 material. © 2012 Elsevier B.V.
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Ferrimagnetism, Magnetic properties, Multiferroic materials, Valence fluctuations, Antiferro-magnetic interactions, Cation distributions, Charge ordering, Curie-Weiss temperature, Ionic radius, Magnetic characterization, Mn ions, Multiferroics, Non-centrosymmetric, Octahedral sites, Parent compounds, Space Groups, Spinel oxide, SQUID magnetometry, Structural and magnetic properties, Bismuth, Carbon dioxide, Characterization, Cobalt, Ferrimagnetic materials, Ions, Jahn-Teller effect, Magnetization, Manganese, Manganese oxide, X ray diffraction, Cobalt compounds
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Journal of Magnetism and Magnetic Materials, v. 329, p. 53-58.