Sr位Nd掺杂对SrBi$lt;sub$gt;2$lt;/sub$gt;Nb$lt;sub$gt;2$lt;/sub$gt;O$lt;sub$gt;9$lt;/sub$gt;性能的影响及机理研究

采用传统固相法制备了（Sr_1-3x/2A_x/2Nd_x）Bi₂Nb₂O₉（x=0，0.05，0.1和0.2）陶瓷，并系统研究了Nd离子取代Sr离子对SrBi₂Nb₂O₉性能的影响及其作用机理.研究结果表明：Sr_1-3x/2A_x/2Nd_xBi₂Nb₂O₉的介电常数和介电损耗随温度变化的行为具有明显的离子松弛极化特征.Nd³⁺对Sr²⁺的部分取代，导致Sr_1-3x/2A_x/2Nd_xBi₂Nb₂O₉剩余极化强度P_r稍有下降，但其压电系数d₃₃却有所增加，根据铁电热力学理论，这是Nd³⁺对Sr²⁺取代导致材料介电常数增大所致.Sr_1-3x/2A_x/2Nd_xBi₂Nb₂O₉的居里温度（T_C）没有随Nd含量的增加而变化，拉曼光谱技术分析表明这是其NbO₆八面体畸变程度没有发生变化所致.Nd³⁺取代Sr²⁺提高了材料的介电常数ε_r、压电系数d₃₃、机电耦合系数K_p，同时降低了机械品质因数Q_m，但是谐振频率温度系数C值没有改变. 关键词： 压电陶瓷 介电性能 压电性能 拉曼光谱

Effects of substitutions of Nd3+ for Sr2+ on the properties of SrBi2Nb2O9 ceramics and their mechanism

（Sr_1-3x/2A_x/2Nd_x）Bi₂Nb₂O₉ （x=0，0.05，0.1 and 0.2） ceramics are prepared by traditional solid-reaction method， and effects of substitutions of Nd³⁺ for Sr²⁺ on the properties of SrBi₂Nb₂O₉ ceramics and their mechanism are investigated. The results show that the temperature spectra of dielectric constant and loss for these Nd-doped samples are obviously characteristic of ion relaxor polarization. The partial substitution of Nd³⁺ for Sr²⁺ leads to the slight reduction in remanent polarization （P_r） and the increase in piezoelectric coefficient d₃₃， which can be attributed to the increase in dielectric constant of samples according to ferroelectric thermodynamics theory. Raman spectrum shows that no change in the Curie temperature （T_C） of （Sr_1-3x/2A_x/2Nd_x） Bi₂Nb₂O₉ samples is observed， which might result from no appreciable variation in NbO₆ octahedron distortion. For （Sr_1-3x/2A_x/2Nd_x） Bi₂Nb₂O₉ ceramics， the substitution of Nd³⁺ for Sr²⁺ increases permittivity ε_r， piezoelectric coefficient d₃₃，and electromechanical coupling coefficient K_p and reduces mechanical quality factor Q_m, but it does not change temperature coefficient of harmonic frequency value.