Facultatea de Fizică
Universitatea "Al.I.Cuza" Iaşi
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| Titlu: Electric properties of (Ni,Zn)Fe2O4-BaTiO3 composites |
| Autori: Cipriana Padurariu1, Lavinia-Petronela Curecheriu1, Maria Teresa Buscaglia2, Vincenzo Buscaglia2, Liliana Mitoseriu1 |
| Afiliere: 1Physics, University Alexandru Ioan Cuza, Iasi, Romania 2Inst. for Energetics & Interphases , CNR, Genova, Italia |
| Abstract: The nanoscale coating of particles of a material with a dissimilar compound is an effective tool to engineer their surface, microstructural characteristics and functional properties. In the present work, di-phasic ceramic composites with core-shell nanostructures formed by Ni0.50Zn0.50Fe2O4 core and BaTiO3 shell were investigated. Their electrical properties were compared with those of composites preparared 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 co-precipitated 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 BaTiO3 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 hoping conductivity, mainly due to the ferrite low resistivity phase. Acknowledgments: This work was supported by POSDRU FSE-POSDRU 89/1.5/S/49944 |
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