Crystal structure, magnetic and dielectric behavior of h-LuMnxO3 +/-delta ceramics (0.95 <= x <= 1.04)
authors Baghizadeh, A; Vieira, JM; Amaral, JS; Graca, MP; Soares, MR; Mota, DA; Amaral, VS
nationality International
journal JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
author keywords Multiferroic; Hexagonal LuMnO3; Vacancy; Magnetoelectric coupling
keywords HEXAGONAL MANGANITES; YMNO3; LUMNO3; YTTRIUM; SCMNO3; PHASE; AIR
abstract 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
publisher ELSEVIER SCIENCE BV
issn 0304-8853
year published 2015
volume 395
beginning page 303
ending page 311
digital object identifier (doi) 10.1016/j.jmmm.2015.07.082
web of science category Materials Science, Multidisciplinary; Physics, Condensed Matter
subject category Materials Science; Physics
unique article identifier WOS:000360025900045
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