中国物理B ›› 2007, Vol. 16 ›› Issue (7): 2131-2135.doi: 10.1088/1009-1963/16/7/056

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Oxygen-vacancy-related dielectric relaxation and conduction mechanisms in Bi5 TiNbWO15 ceramics

王晓娟1, 龚志强1, 钱亚峰1, 朱骏1, 陈小兵2   

  1. (1)College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China; (2)College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China;The National Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210008, China
  • 收稿日期:2006-11-16 修回日期:2006-12-14 出版日期:2007-07-20 发布日期:2007-07-04
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10274066) and the Natural Science Foundation of Jiangsu Province, China (Grant No BK2005052).

Oxygen-vacancy-related dielectric relaxation and conduction mechanisms in Bi5 TiNbWO15 ceramics

Wang Xiao-Juan(王晓娟)a), Gong Zhi-Qiang(龚志强)a), Qian Ya-Feng(钱亚峰)a), Zhu Jun(朱骏)a), and Chen Xiao-Bing(陈小兵)a)b)†   

  1. a College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China; b The National Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210008, China
  • Received:2006-11-16 Revised:2006-12-14 Online:2007-07-20 Published:2007-07-04
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10274066) and the Natural Science Foundation of Jiangsu Province, China (Grant No BK2005052).

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摘要： This paper reports that the intergrowth ceramics Bi5TiNbWO15 (BW-BTN) have been prepared with the conventional solid-state reaction method. The dielectric and conductivity properties of samples were studied by using the dielectric relaxation and AC impedance spectroscopy in detail. Two distinct relaxation mechanisms were detected both in the plots of dielectric loss (tan\delta) and the imaginary part ({Z}'') versus frequency in the frequency range of 10 Hz--13MHz. We attribute the higher frequency relaxation process to the hopping process of the oxygen vacancies inside the grains, while the other seems to be associated with the space charges bound at the grain boundary layers. The AC impedance spectroscopy indicates that the conductivities at 625K for bulk and grain boundary are about 1.12\times10-3S/m and 1.43\times10-3S/m respectively. The accumulation of the space charges in the grain boundary layers induces a space charge potential of 0.52eV.

关键词: intergrowth, dielectric relaxation, impedance spectroscopy, oxygen vacancies

Abstract: This paper reports that the intergrowth ceramics Bi5TiNbWO15 (BW-BTN) have been prepared with the conventional solid-state reaction method. The dielectric and conductivity properties of samples were studied by using the dielectric relaxation and AC impedance spectroscopy in detail. Two distinct relaxation mechanisms were detected both in the plots of dielectric loss (tan$\delta$) and the imaginary part (Z'') versus frequency in the frequency range of 10 Hz--13MHz. We attribute the higher frequency relaxation process to the hopping process of the oxygen vacancies inside the grains, while the other seems to be associated with the space charges bound at the grain boundary layers. The AC impedance spectroscopy indicates that the conductivities at 625K for bulk and grain boundary are about 1.12\times10-3S/m and 1.43\times10-3S/m respectively. The accumulation of the space charges in the grain boundary layers induces a space charge potential of 0.52eV.

Key words: intergrowth, dielectric relaxation, impedance spectroscopy, oxygen vacancies

中图分类号:  (Dielectric loss and relaxation)

  • 77.22.Gm
61.72.J- (Point defects and defect clusters) 61.72.Mm (Grain and twin boundaries) 72.80.-r (Conductivity of specific materials) 77.22.Jp (Dielectric breakdown and space-charge effects)