Ni/Pb(Zr,Ti)O3/TbFe2层状复合材料的谐振磁电特性研究

采用化学镀和黏接法制备层状磁电复合材料Ni/PZT/TbFe₂,研究其磁电性能及谐振频率随Ni层厚度的变化情况. 结果表明:Ni/PZT/TbFe₂层状磁电复合材料与其他结构的磁电性能不同,其一阶弯曲谐振峰值和纵向谐振峰值都很大. 随着Ni层厚度的增加,Ni/PZT/TbFe₂层状磁电复合材料的一阶纵向谐振峰值逐渐增大. 结合实验数据和理论计算值得出了材料的一阶弯曲谐振频率fr1和一阶纵向谐振频率f 关键词： 磁电效应 正磁致伸缩 负磁致伸缩 谐振频率     

α-Al2O3相变机理及制备工艺研究进展

α-Al₂O₃在耐火材料、电子材料等多个领域有着极其重要的应用。本文首先介绍了α-Al₂O₃在工业应用方面的评价指标和α-Al₂O₃的相变机理,接着分别从固相合成、液相合成、气相合成三个方面阐述了α-Al₂O₃制备的相关研究进展,对制备过程中影响α-Al₂O₃晶粒微观状态的若干因素,包括煅烧温度、矿化剂类型、pH值及预处理条件等进行讨论。最后指出了当前对α-A1₂O₃成核生长机理研究缺乏的问题,表明明确的成核机理、高纯度α-A1₂O₃的量产和形貌控制技术将会是该领域未来的研究重点和发展方向。     

Magnetoelectric effect in layered composites with arc shape

Magnetoelectric (ME) layered Ni/PZT/Ni composites with arc shape have been prepared by using electroless deposition. The ME effect is measured by applying both constant and alternating magnetic fields in longitudinal and transverse directions. The longitudinal ME voltage coefficient is much larger than the transverse one. With the increase of arc length or decrease of curvature, the resonance frequency of layered arc Ni/PZT/Ni composites gradually decreases, while the maximum of the ME voltage coefficient of the composites increases monotonously. The influence of the arc length and the curvature on ME coupling is discussed. The flat interface between the ferromagnetic and the piezoelectric phases in layered ME composites is believed to provide large ME voltage coefficient.