Enhanced dielectric response of GeO{sub 2}-doped CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics

Journal Article · Sun Feb 01 00:00:00 EST 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3075909· OSTI ID:21186017

Amaral, F ^[1]; Rubinger, C P. L. ^[1]; Valente, M A; Costa, L C ^[1]; Moreira, R L ^[2]

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1. Department of Physics, I3N, Aveiro University, 3810-193 Aveiro (Portugal)
2. Department of Physics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais 31270-901 (Brazil)

CaCu{sub 3}Ti{sub 4}O{sub 12} ceramic samples were prepared by solid state conventional route using stoichiometric amounts of CuO, TiO{sub 2}, and CaCO{sub 3}. Afterward the material was doped with GeO{sub 2} with concentrations up to 6% by weight and sintered at 1050 deg. C for 12 h. The influence of doping on the microstructure, vibrational modes, and dielectric properties of the material was investigated by x-ray diffraction, scanning electron microscopy coupled with an energy dispersive spectrometer, and infrared and dielectric measurements between 100 Hz and 30 MHz. The materials presented huge dielectric response, which increases with doping level relative to undoped CaCu{sub 3}Ti{sub 4}O{sub 12}. The main effect of doping on the microstructure is the segregation of Cu-rich phase in the ceramic grain boundaries. Cole-Cole modeling correlates well the effects of this segregation with the relaxation parameters obtained. The intrinsic phonon contributions for the dielectric response were obtained and discussed together with the structural evolution of the system.

• OSTI ID: 21186017
• Journal Information: Journal of Applied Physics, Vol. 105, Issue 3; Other Information: DOI: 10.1063/1.3075909; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM CARBONATES
CERAMICS
CHEMICAL ANALYSIS
COPPER OXIDES
DIELECTRIC MATERIALS
DOPED MATERIALS
GERMANIUM OXIDES
GRAIN BOUNDARIES
INFRARED SPECTRA
MHZ RANGE 01-100
PERMITTIVITY
PHONONS
SCANNING ELECTRON MICROSCOPY
SEGREGATION
SINTERING
SPECTROMETERS
STOICHIOMETRY
TITANIUM OXIDES
X-RAY DIFFRACTION