Electric-field dependence of dielectric properties of sol-gel derived Ba(Zr0.2Ti0.8)O3 ceramics |
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Authors: | X G Tang Q X Liu J Wang and H L W Chan |
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Institution: | (1) School of Physics and Optoelectric Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People’s Republic of China;(2) Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People’s Republic of China |
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Abstract: | The effect of a dc bias field on the diffuse phase transition and nonlinear dielectric properties of sol-gel derived Ba(Zr0.2Ti0.8)O3 (BZT) ceramics are investigated. Diffuse phase transitions were observed in BZT ceramics and the Curie–Weiss exponent (CWE)
was γ∼2.0. The dielectric constant versus temperature characteristics and the γ in the modified Curie–Weiss law, ε
−1=ε
m
−11+(T−T
m
)
γ
/C1](1≤γ≤2), as a function of the dc bias field was obtained for BZT ceramics. The results indicated that γ is a function of dc bias field, and the γ value decreased from 2.04 to 1.73 with dc bias field increasing from 0 to 20 kV/cm. The dielectric constant decreases with
increasing dc bias field, indicating a field-induced phase transition. The dc bias field has a strong effect on the position
of the dielectric peak and affects the magnitude of the dielectric properties over a rather wide temperature range. The peak
temperature of the dielectric loss does not coincide with the dielectric peak and an obvious minimum value for the dielectric
loss at the temperature of the dielectric peaks is observed. At room temperature, 300 K, the high tunability (K=80%), the low loss tangent (≈0.01) and the large FOM (74), clearly imply that these ceramics are promising materials for tunable capacitor-device applications. |
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Keywords: | PACS" target="_blank">PACS 77 84 Dy 77 22 Ch 77 22 Gm 77 80 Bh 81 30 Hd |
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