• Title, Summary, Keyword: modified Curie-Weiss law

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Effects of Nb5+ Addition on Microstructure and Dielectric Properties of BaTiO3

  • Kim, Yeon Jung;Hyun, June Won
    • Applied Science and Convergence Technology
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    • v.26 no.5
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    • pp.143-147
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    • 2017
  • Structural studies on the addition characteristics of Nb ions to $BaTiO_3$ solid solutions were performed by XRD and SEM/EDS technique. The X-ray diffraction peaks of the (111), (200) and (002) planes of Nb-doped $BaTiO_3$ solid solutions with different mole% of Nb were analyzed. We also investigated the relationship between the dielectric and structural properties of Nb-doped $BaTiO_3$. The transition temperatures of $BaTiO_3$ solid solution doped with 0.5mole%Nb and 1.0 mole%Nb were ${\sim}116^{\circ}C$ and ${\sim}87^{\circ}C$, respectively, which were found to be shifted to very low temperature from the transition temperature of pure $BaTiO_3$ (about $125^{\circ}C$). As a result of analysis of 1/K versus T and ln[$(1/K)-(1/K_m)$ versus ($T-T_m$)] of the two compositions used in this experiment, the diffusivity slightly differs from that of pure $BaTiO_3$ at temperatures above Curie temperature. And this characteristic was analyzed by applying the modified Curie-Weiss law.

Relaxor Behaviors in xBaTiO3-(1-x)CoFe2O4 Materials

  • Dung, Cao Thi My;Thi, Nhu Hoa Tran;Ta, Kieu Hanh Thi;Tran, Vinh Cao;Nguyen, Bao Thu Le;Le, Van Hieu;Do, Phuong Anh;Dang, Anh Tuan;Ju, Heongkyu;Phan, Bach Thang
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.353-359
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    • 2015
  • Dielectric properties of $xBaTiO_3-(1-x)CoFe_2O_4$ composite materials have been investigated. Dielectric properties of $BaTiO_3$, $CoFe_2O_4$ and $0.5BaTiO_3-0.5CoFe_2O_4$ samples show frequency dependence, which is classified as relaxor behavior with different relaxing degree. The relaxor behaviors were described using the modified Curier-Weiss and Vogel-Fulcher laws. Among three above samples, the $BaTiO_3$ sample has highest relaxing degree. Photoluminescence spectral indicated defects, which might in turn control relaxing degree.