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Author Curecheriu, L. P. ♦ Mitoseriu, L. ♦ Postolache, P. ♦ Buscaglia, M. T. ♦ Buscaglia, V. ♦ Ianculescu, A. ♦ Nanni, P.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ BARIUM COMPOUNDS ♦ CERAMICS ♦ COMPOSITE MATERIALS ♦ COPRECIPITATION ♦ DIELECTRIC PROPERTIES ♦ FERRITES ♦ FERROELECTRIC MATERIALS ♦ MAGNETIC PROPERTIES ♦ MATRIX MATERIALS ♦ MICROSTRUCTURE ♦ NANOSTRUCTURES ♦ NICKEL COMPOUNDS ♦ POWDERS ♦ RELAXATION ♦ SPACE CHARGE ♦ TITANATES ♦ ZINC COMPOUNDS ♦ ALKALINE EARTH METAL COMPOUNDS ♦ DIELECTRIC MATERIALS ♦ ELECTRICAL PROPERTIES ♦ FERRIMAGNETIC MATERIALS ♦ IRON COMPOUNDS ♦ MAGNETIC MATERIALS ♦ MATERIALS ♦ OXYGEN COMPOUNDS ♦ PHYSICAL PROPERTIES ♦ PRECIPITATION ♦ SEPARATION PROCESSES ♦ TITANIUM COMPOUNDS ♦ TRANSITION ELEMENT COMPOUNDS
Abstract In the present work, diphasic ceramic composites with core-shell nanostructures formed by Ni{sub 0.50}Zn{sub 0.50}Fe{sub 2}O{sub 4} core and BaTiO{sub 3} shell were investigated. Their properties were compared with those of composites prepared by coprecipitation. The core-shell structure was confirmed by microstructural powder analysis. Homogeneous microstructures with a good phase mixing and percolated dielectric phase by the magnetic one were obtained from coprecipitated powders. Less homogeneous microstructures resulted in ceramics produced from the powder prepared by core-shell method, with isolated small ferrite grains besides large ferrite aggregates embedded into the BaTiO{sub 3} matrix. Both the ferroelectric and magnetic phases preserve their basic properties in bulk composite form. However, important differences in the dielectric relaxation and conduction mechanisms were found as result of the microstructural difference. Extrinsic contributions play important roles in modifying the electric properties in both ceramics, causing space charge effect, Maxwell-Wagner relaxations and hopping conductivity, mainly due to the ferrite low resistivity phase. The conductivity and dielectric modulus spectra analysis allowed to identify different polaron contributions associated with the microstructural differences. It results that by using the core-shell method, improved dielectric properties and limited hopping contributions can be realized.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2010-05-15
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 107
Issue Number 10


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