Broadband dielectric spectroscopy of standard and core-shell BaTiO.sub.3./sub.-NiO ceramic composites compared to the BaTiO.sub.3./sub. ceramics

0465087 - FZÚ 2017 RIV GB eng J - Journal Article
Nuzhnyy, Dmitry - Petzelt, Jan - Bovtun, Viktor - Ostapchuk, Tetyana - Savinov, Maxim - Kempa, Martin - Bednyakov, Petr - Fernández-Garciá, L. - Rodriguez-Suarez, T. - Menendéz, J.L.
Broadband dielectric spectroscopy of standard and core-shell BaTiO₃-NiO ceramic composites compared to the BaTiO₃ ceramics.
Ferroelectrics. Roč. 500, č. 1 (2016), s. 1-19. ISSN 0015-0193. E-ISSN 1563-5112
R&D Projects: GA ČR GA15-08389S
Institutional support: RVO:68378271
Keywords : core-shell composite * effective dielectric function * effective infrared response * effective medium approximation * percolation * barium titanate * nickel oxide
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 0.551, year: 2016

Using SPS we have processed and studied two ceramic composites of 70 vol% BaTiO3 and 30 vol% NiO with different topologies: standard and core-shell composites. The materials were characterized by XRD and SEM and studied by quantitative broadband dielectric spectroscopy up to the infrared range using four different spectroscopic techniques in the 10-450 K temperature range. The spectra were fitted with the factorized dielectric function of generalized damped oscillators in the infrared-terahertz range and by a set of Cole-Cole relaxations at lower frequencies below the polar phonon frequency range. Using the dielectric functions of the BaTiO3 ceramics and NiO crystal, we modelled the effective dielectric functions of the composite using three models based on the effective medium approximation: Bruggeman, Lichtenecker and generalized brick model (coated spheres). Qualitative agreement between the experimental and modelled effective dielectric functions was obtained.

Permanent Link: http://hdl.handle.net/11104/0264073