Functional properties of BaTiO{sub 3}-Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} magnetoelectric ceramics prepared from powders with core-shell structure

Journal Article · Sat May 15 00:00:00 EDT 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3340844· OSTI ID:21476262

Curecheriu, L P; Mitoseriu, L; Postolache, P ^[1]; Buscaglia, M T; Buscaglia, V ^[2]; Ianculescu, A ^[3]; Nanni, P ^[2]

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1. Department of Physics, Al. I. Cuza University, Bv. Carol I, no. 11, Iasi 700506 (Romania)
2. Institute for Energetics and Interphases, CNR, Via de Marini no. 6, Genoa I-16149 (Italy)
3. Department of Oxide Materials Science and Engineering, Polytechnics University, 1-7 Gh. Polizu, P.O. Box 12-134, Bucharest 011061 (Romania)

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.

• OSTI ID: 21476262
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 10; Other Information: DOI: 10.1063/1.3340844; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 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