Nb掺杂对（Sr，Pb）TiO_3基陶瓷半导体晶粒及晶界导电特性的影响

Influence of Nb Doping on the Grain and Grain Boundary Electrical Properties of (Sr,Ph)TiO_3-Based Ceramic Semiconductors

研究了施主掺杂的（Ｓｒ，Ｐｂ）ＴｉＯ３陶瓷，探讨不同的施主Ｎｂ掺杂浓度对材料电阻率和显微结构的影响。通过复阻抗解析，分别得到施主浓度的变化对材料晶粒和晶界电阻率的影响规律。结果表明随施主浓度的增加，晶粒和晶界电阻率变化呈现相似的Ｕ型曲线，但晶界的电阻率值及变化幅度远大于晶粒，证明了晶界对材料的电阻特性起主导作用。

The donor- doped (Sr,Pb)TiO3 ceramics were investigated. The effects of different Nb-doping concentrations on resistivities of the materials and microstructures were discussed. The relationshiPS betiveen different Nb concentrations and grains and grain boundaries were obtained by means of complex impedance spectroscopy at room temperature. The experimental results indicate that with the increase of donor concentration the resistivities of grain and grain boundary take on the similar U-type curve. The change of resistivities of grain boundary is far more than that of grain. It proves the leading effect of grain boundary on the resistivity of (Sr, Pb)TiO3 ceramics.