中国物理B ›› 2011, Vol. 20 ›› Issue (4): 48701-048701.doi: 10.1088/1674-1056/20/4/048701
袁昌来1, 刘心宇1, 周昌荣2, 许积文2, 杨云2
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)
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.
中图分类号: (Dielectric properties)