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Title: Cu-doping effect on dielectric properties of organic gel synthesized Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ}

Copper doped-Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ} samples were synthesized by an organic gel assisted citrate process. X-ray diffraction of compositions with x=0.002, 0.005, 0.01, 0.02 and 0.04 does not reveal any change of hexagonal perovskite structure on doping. The effects of Cu-doping on the microstructure and dielectric properties were investigated. Cu doping modifies the electrical properties at the level of the impedance characteristics of both grain and grain boundary and to understand these different behaviours, we have carried out high-resolution transmission electron microscopy analysis. Among the Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ} specimens studied, the composition x=0.002 shows a permittivity (ε′{sub r}) higher than the undoped compound and a lower loss tangent (tanδ) over several orders of magnitude of frequency. - Graphical abstract: Highlighting of many stacking faults (intergrowths) in substituted compounds with x>0.01 (right picture), which could explain the different dielectric properties observed in these compounds. However compounds with x>0.01 remain with a better stacking sequence as we can see on the left picture. Display Omitted - Highlights: • High permittivity of the Ba{sub 4}YMn{sub 3−x}Cu{sub x}O{sub 11.5±δ}. • Substitution leads to a mixed oxidation state for manganese: Mn{sup 4+}/Mn{sup 3+}. • Creation of oxygen vacancies which are responsible formore » stacking faults. • Highlighting relationship between Cu substitution and dielectric properties.« less
Authors:
 [1] ;  [1] ;  [2] ; ;  [1] ;  [3] ; ;  [1]
  1. Université François Rabelais de Tours, CNRS, CEA, ENIVL, GREMAN UMR 7347, 37200 Tours (France)
  2. Centre de Recherche sur la matière divisée (CRMD), Université d'Orléans, CNRS, FRE3520, 1B rue de la Férollerie, 45071 Orléans (France)
  3. CEA—DAM, Le Ripault, 37260 Monts (France)
Publication Date:
OSTI Identifier:
22274126
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 206; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHEMICAL PREPARATION; CITRATE PROCESS; DOPED MATERIALS; GELS; GRAIN BOUNDARIES; MANGANESE; MANGANESE IONS; PERMITTIVITY; PEROVSKITE; STACKING FAULTS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION