Comparative dielectric studies of nanostructured BaTiO{sub 3}, CaCu{sub 3}Ti{sub 4}O{sub 12} and 0.5BaTiO{sub 3}⋅ 0.5CaCu{sub 3}Ti{sub 4}O{sub 12} nano-composites synthesized by modified sol–gel and solid state methods

Journal Article · Wed Oct 15 04:00:00 EDT 2014 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2014.07.019· OSTI ID:22403561

Singh, Laxman ^[1]; Rai, Uma Shanker ^[2]; Mandal, Kam Deo ^[3]; Sin, Byung Cheol; Lee, Hyung-il ^[1]; Chung, Hoeil ^[4]; Lee, Youngil ^[1]

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1. Department of Chemistry, University of Ulsan, 93 Daehak-ro Nam-gu, Ulsan 680-749 (Korea, Republic of)
2. Department of Chemistry, Centre of Advanced Study, Faculty of Science, Banaras Hindu University, Varanasi 221005, U.P. (India)
3. Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, U.P. (India)
4. Department of Chemistry, Hanyang University, Haengdang-dong 17, Seongdong-Gu, Seoul 133-791 (Korea, Republic of)

BaTiO{sub 3} (BTO), CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) and 0.5BaTiO{sub 3}·0.5CaCu{sub 3}Ti{sub 4}O{sub 12} (BTO–CCTO), as a new nano-composite ceramic, were successfully designed and fabricated by a semi-wet gel route and a modified solid state method. The dielectric properties of the BTO–CCTO ceramic were compared to those of the BTO and CCTO ceramics at lower sintering temperatures and durations. The X-ray diffraction analysis revealed that the BTO and CCTO ceramics form a single crystalline phase and the average crystalline sizes calculated from X-ray diffraction data were in the range of 40–65 nm. The particle sizes of the BTO, CCTO, and BTO–CCTO ceramics obtained from transmission electron microscopy images were in the ranges of 40–65 nm, 80–110 nm, and 70–95 nm, respectively. The phase composition and microstructure were studied by X-ray diffraction and scanning electron microscopy. The energy dispersive X-ray results demonstrated the purity and stoichiometry of the BTO–CCTO nano-composite. The grain sizes of the BTO, CCTO and BTO–CCTO ceramics were found to be in the ranges of 500 nm–1 μm, 4–24 μm, and 250 nm–4 μm, respectively. The AC conductivity as a function of frequency confirmed the semiconducting nature of all of the ceramics and obeyed the Jonscher's power law. The impedance spectrum measurement result showed that the CCTO ceramic possessed an exceptional grain boundary resistance, which supports the internal barrier layer capacitance (IBLC) mechanism present in this ceramic and is responsible for the high ε{sub r} values. - Highlights: • Nanostructured BaTiO{sub 3}, CaCu{sub 3}Ti{sub 4}O{sub 12}, and 0.5BaTiO{sub 3}⋅ 0.5CaCu{sub 3}Ti{sub 4}O{sub 12} have been synthesized. • XRD and TEM analysis confirmed the formation of nanoparticles, 40–65 and 50–90 nm. • Impedance analysis shows high grain-boundary resistance present in CCTO ceramic. • AC conductivity as a function of frequency confirms the semiconducting nature.

• OSTI ID: 22403561
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 96; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CERAMICS
COMPARATIVE EVALUATIONS
DEPLETION LAYER
DIELECTRIC MATERIALS
DIELECTRIC PROPERTIES
FREQUENCY DEPENDENCE
GRAIN BOUNDARIES
GRAIN SIZE
MONOCRYSTALS
NANOPARTICLES
NANOSTRUCTURES
PARTICLE SIZE
SCANNING ELECTRON MICROSCOPY
SINTERING
SOL-GEL PROCESS
TITANATES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION