skip to main content

SciTech ConnectSciTech Connect

Title: 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

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.more » 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.« less
Authors:
 [1] ;  [2] ;  [3] ; ;  [1] ;  [4] ;  [1]
  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)
Publication Date:
OSTI Identifier:
22403561
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 96; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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