La诱导(Pb(1-3x/2)Lax)(Zr0.5Sn0.3Ti0.2)O3反铁电介电弛豫研究

采用标准电子陶瓷工艺制备了(Pb_(1-3x/2)La_x)(Zr_0.5Sn_0.3Ti_0.2)O₃(PLZST,0.00≤x≤0.18)反铁电陶瓷,利用X射线衍射、不同频率下弱场介电温谱、强场下的极化强度-电场(P-E)测试研究了材料相结构和电学性能.实验结果发现,随La含量x增大,室温下材料由铁电三方相(关键词： 反铁电陶瓷 介电频率色散 相变弥散 介电弛豫

Dielectric relaxation of(Pb(1-3x/2)Lax)(Zr0.5 Sn0.3 Ti0.2)O3 antiferroelectric ceramics induced by lanthanum doping

The (Pb_(1-3x/2)La_x)(Zr_0.5Sn_0.3Ti_0.2)O₃(PLZST, 0.00≤x≤0.18)antiferroelectric ceramics were prepared by traditional ceramic process. The effect of La modification on phase structures, phase transition, and electrical properties of PLZST ceramics were investigated by X-ray diffraction, P-E hysteresis loop and dielectric spectroscopy. With the increase of La content x,the samples at room temperature are rhombohedral ferroelectric phase (x≤0.0.04),tetragonal antiferroelectric phase(AFE_t, 0.06<x≤0.0.08, and cubic phase (PE' _{cx≥0.1), respectively. The dielectric spectroscopy shows that with the increase of La content x, AFE-PE phase transformation temperature decreases, and for samples with La content x exceeding 0.12, strong dielectric frequency dispersion is observed around dielectric ε' and tanδ peaks. The peak temperatures Tm corresponding to the maxim dielectric constant shifts to higher temperatures with the increase of frequency, indicating that PLZST antiferroelectric transform to typical relaxors. The curves of dielectrics as functions of temperatures in the PLZST systems are fitted by a modified Curie–Weiss law proposed by Santos.}