【摘要】 制备了扩散相转变铁电陶瓷系列(Ba_1-xLa_x)（Ti（1-y）Zr_y）O₃和扩散-非扩散相变铁电单晶系列K_0.2Na_0.2(Sr_pBa_1-p)_0.8Nb₂O₆。陶瓷采用一般铁电陶瓷制备工艺,单晶采用提拉法生长。测量了所有样品在-50—100℃范围内介电常数随温度的变化曲线。采用X射线能谱仪和扫描电子显微镜对样品进行了半定量成份分布分析。发现在扩散相变材料中存在着明显的成份不均匀性。而这种现象在尖峰相变材料中几乎没有。ε（T）曲线的展宽程度与成份对平均值的偏差大小直接有关,从而为Smnolensky的成份涨落模型提供了直接的实验根据。DPT材料内部存在转变温度的统计分布函数。用两种不同的ε′（T,T_c）表达式对所有样品的ε（T）曲线进行了计算,结果与实验较好地相符。更多还原

【Abstract】 A DPT ferroelectric ceramics system of (Ba1-xLax) (Ti1-yZry) O3 and a DPT-SPT ferroelectric crystal serise of K0.2 Na0.2 (SrpBa1-p)0.8Nb2O6 have beenprepared by the ordinary ceramics manufacture technique and Czochralski technique respectively. The curves of dielectric constant vs. temperature of all samples have been measured. The semi-quantitive point-analyses of composition distribution have been obtained by the technique of SBM and EDAX. The inhomogeneity of composition distribution was discovered in both DPT ceramicses and DPT single crystal, but in SPT crystal no such fluctuation was found. It was shown that the diffuse curves of ε(T) is related to composition fluctuation directly. Therefore the Smolensky’s composition fluctuation model for DPT was proved in experiment. According to this model, there is a statistical distribution of transition temperature, inside the DPT ferroelectrics. The theoretical calculation of dielectric constant with the change of temperature of all samples were done by using two different expressions of ∈’(T, Tc). The theoretical results agree well with experimental curves.更多还原