【摘要】 研究了Ｚｒ／Ｔｉ比为６５／３５、掺Ｌａ分别为８、９、１２、１６．７％（ｍｏｌ％）的锆钛酸铅镧（ＰＬＺＴ８／６５／３５、９／６５／３５、１２／６５／３５、１６．７／６５／３５）陶瓷的微结构和介电性能。ＸＲＤ研究表明，ＰＬＺＴ中存在着｛ｈ＋１２，ｋ＋１２，ｌ｝型超结构；随着Ｌａ含量的增加，有序度增加，当Ｌａ含量为１２％时达到最大，继之下降。提出了Ａ位离子有序的体心立方超结构模型。介电常数与温度关系研究表明，随着Ｌａ含量的增加，弥散相变度参数δ单调上升，而频率色散度参数ΔＴ０先是增加，然后下降。表明其介电弛豫行为与Ｌａ含量密切相关。更多还原

【Abstract】 The microstructure and dielectric behavior of lanthanum modified lead zirconate titanate relaxors with different lanthanum content (8,9,12,16.7at%)and a Zr/Ti ratio of 65/35 (PLZT8/65/35、9/65/35、12/65/35、16.7/65/35) were investigated. X ray diffraction experiments revealed that{h+12,k+12,l} type superlattice exists in the samples. The ordering degree increased with increasing of La content and reached the maxima when La content was near 12.5at%, but then decreased with La content further increasing. An ordered model with body centered cubic superstructure on A site cations was proposed. The dielectric properties of PLZT were investigated, showing that the relaxor behavior of the samples was very sensitive to La concentration. The diffusive parameter (δ),increased continually with La content increasing, the dissipation factor (ΔT 0) first increased, but then decreased with La content increasing. The mechanism of the relaxor behavior was discussed.更多还原