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http://hdl.handle.net/10773/20683
Título: | Crystal structure, magnetic and dielectric behavior of h-LuMnxO3 +/-delta ceramics (0.95 <= x <= 1.04) |
Autor: | Baghizadeh, A. Vieira, J. M. Amaral, J. S. Graca, M. P. Soares, M. R. Mota, D. A. Amaral, V. S. |
Palavras-chave: | HEXAGONAL MANGANITES YMNO3 LUMNO3 YTTRIUM SCMNO3 PHASE AIR |
Data: | 2015 |
Editora: | ELSEVIER SCIENCE BV |
Resumo: | Lattice constants, magnetic properties and dielectric behavior of h-LuMnxO3 +/-delta solid solution (0.95 <= x <= 1.04) of bulk ceramic samples prepared by the solid state reaction method were studied to determine the role of stoichiometry changes on the crystalline structure and magneto-electric coupling. It is found that increasing of Mn content results in reduction of cell volume of h-LuMnxO3 +/-delta ceramics mostly due to shrinkage of a-axis length. The antiferromagnetic interactions of Mn3+ ions weaken with cell volume contraction. A weak ferromagnetic contribution appeared in all samples and extends up to the Neel temperature, T-N. Irreversibility in temperature dependent magnetic measurements already reported for stoichiometric compositions of hexagonal RMnO3 oxides appears for all h-LuMnxO3 +/-delta samples right below Neel ordering transition. An increase of magnetic coercive field and magnetization on cooling below T-N in samples is observed in field dependent magnetization and rises as x increases. In addition to the antiferromagnetic ordering transition at T-N, two anomalies of the temperature dependent magnetic susceptibility and dielectric constant are identified below T-N, centered at 69 K and 31 K respectively, being probably due to inhomogeneity of the crystalline structure inside ceramic grains. Changes of the dielectric constant at T-N can be attributed to magneto-electric coupling in the off-stoichiometric hexagonal LuMnxO3+delta lattice. The behavior of the dielectric relaxation follows a thermally activated mechanism with activation energy values characteristic of polaron hoping. (C) 2015 Elsevier B.V. All rights reserved |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/20683 |
DOI: | 10.1016/j.jmmm.2015.07.082 |
ISSN: | 0304-8853 |
Versão do Editor: | 10.1016/j.jmmm.2015.07.082 |
Aparece nas coleções: | CICECO - Artigos |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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Crystal structure magnetic and dielectric behavior of h-LuMnxO3 +-delta ceramics (0.95 = x = 1.04)_10.1016j.jmmm.2015.07.082.pdf | 2.43 MB | Adobe PDF |
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