中国物理B ›› 2011, Vol. 20 ›› Issue (4): 48701-048701.doi: 10.1088/1674-1056/20/4/048701

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boldmath Characterization of the BaBiO3-doped BaTiO3 positive temperature coefficient of a resistivity ceramic using impedance spectroscopy with Tc=155℃

袁昌来1, 刘心宇1, 周昌荣2, 许积文2, 杨云2   

  1. (1)College of Materials Science and Engineering, Central South University, Changsha 410083, China;School of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China; (2)School of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China
  • 收稿日期:2010-06-16 修回日期:2010-12-08 出版日期:2011-04-15 发布日期:2011-04-15
  • 基金资助:
    Project supported by the Research Funds of the Guangxi Key Laboratory of Information Materials at the School of Material Science and Engineering, China (Grant No. 0710908-07-Z).

Characterization of the BaBiO3-doped BaTiO3 positive temperature coefficient of a resistivity ceramic using impedance spectroscopy with Tc=155℃

Yuan Chang-Lai(袁昌来)a)b), Liu Xin-Yu(刘心宇)a)b), Zhou Chang-Rong(周昌荣)b), Xu Ji-Wen(许积文)b),and Yang Yun(杨云) b)   

  1. a College of Materials Science and Engineering, Central South University, Changsha 410083, China; b School of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China
  • Received:2010-06-16 Revised:2010-12-08 Online:2011-04-15 Published:2011-04-15
  • Supported by:
    Project supported by the Research Funds of the Guangxi Key Laboratory of Information Materials at the School of Material Science and Engineering, China (Grant No. 0710908-07-Z).

摘要: BaBiO3-doped BaTiO3 (BB-BT) ceramic, as a candidate for lead-free positive temperature coefficient of resistivity (PTCR) materials with a higher Curie temperature, has been synthesized in air by a conventional sintering technique. The temperature dependence of resistivity shows that the phase transition of the PTC thermistor ceramic occurs at the Curie temperature, Tc=155 ℃, which is higher than that of BaTiO3 ( ≤ 130 ℃). Analysis of ac impedance data using complex impedance spectroscopy gives the alternate current (AC) resistance of the PTCR ceramic. By additional use of the complex electric modulus formalism to analyse the same data, the inhomogeneous nature of the ceramic may be unveiled. The impedance spectra reveal that the grain resistance of the BB-BT sample is slightly influenced by the increase of temperature, indicating that the increase in overall resistivity is entirely due to a grain-boundary effect. Based on the dependence of the extent to which the peaks of the imaginary part of electric modulus and impedance are matched on frequency, the conduction mechanism is also discussed for a BB-BT ceramic system.

关键词: BaBiO3-doped BaTiO3, positive temperature coefficient thermistor, impedance spectroscopy, high Tc

Abstract: BaBiO3-doped BaTiO3 (BB–BT) ceramic, as a candidate for lead-free positive temperature coefficient of resistivity (PTCR) materials with a higher Curie temperature, has been synthesized in air by a conventional sintering technique. The temperature dependence of resistivity shows that the phase transition of the PTC thermistor ceramic occurs at the Curie temperature, Tc=155 ℃, which is higher than that of BaTiO3 ( ≤ 130 ℃). Analysis of ac impedance data using complex impedance spectroscopy gives the alternate current (AC) resistance of the PTCR ceramic. By additional use of the complex electric modulus formalism to analyse the same data, the inhomogeneous nature of the ceramic may be unveiled. The impedance spectra reveal that the grain resistance of the BB–BT sample is slightly influenced by the increase of temperature, indicating that the increase in overall resistivity is entirely due to a grain-boundary effect. Based on the dependence of the extent to which the peaks of the imaginary part of electric modulus and impedance are matched on frequency, the conduction mechanism is also discussed for a BB–BT ceramic system.

Key words: BaBiO3-doped BaTiO3, positive temperature coefficient thermistor, impedance spectroscopy, high Tc

中图分类号:  (Dielectric properties)

  • 87.19.rf
84.32.Ff (Conductors, resistors (including thermistors, varistors, and photoresistors)) 81.05.Je (Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)) 82.56.Na (Relaxation)