High-frequency dielectric spectroscopy of BaTiO3 core - silica shell nanocomposites: problem of interdiffusion

0368156 - FZÚ 2012 RIV SG eng J - Journal Article
Nuzhnyy, Dmitry - Petzelt, Jan - Bovtun, Viktor - Kempa, Martin - Savinov, Maxim - Elissalde, C. - Chung, U.-C. - Michau, D. - Estournes, C. - Maglione, M.
High-frequency dielectric spectroscopy of BaTiO3 core - silica shell nanocomposites: problem of interdiffusion.
Journal of Advanced Dielectrics. Roč. 1, č. 3 (2011), 309-317. ISSN 2010-135X
R&D Projects: GA ČR GA202/09/0430
Institutional research plan: CEZ:AV0Z10100520
Keywords : core-shell nanocomposites * infrared and THz spectroscopy * barium titanate * effective medium approximation
Subject RIV: BM - Solid Matter Physics ; Magnetism

Three types of BaTiO3 core - amorphous nanoshell composite ceramics were processed from the same core-shell powder by standard sintering, spark-plasma sintering and two-step sintering techniques and characterized by XRD, HRSEM and broadband dielectric spectroscopy in the frequency range 103-1013 Hz including the THz and IR range. The samples differed by porosity and by the amount of interdiffusion from the cores to shells, in correlation with their increasing porosity. The dielectric spectra were also calculated using suitable models based on effective medium approximation. The measurements revealed a strong dielectric dispersion below the THz range, which cannot be explained by the modeling, and whose strength was in correlation with the degree of interdiffusion. It is assigned to an effect of the interdiffusion layers, giving rise to a strong interfacial polarization.
Permanent Link: http://hdl.handle.net/11104/0202583