镍酸镧界面层对锆钛酸铅膜/钴铁氧体陶瓷复合体系的磁电效应调控

Magnetoelectric composites have attracted considerable attention due to their potential applications in sensors, transducers, etc. In the ferroelectric-film/magnetic-ceramic magnetoelectric composites, the conductivity of the magnetic ceramics plays an important part in the charge collection of the electric-related properties and the resultant characterization of the magnetoelectric effect. The present work focuses on the improvement of charge collection by introducing the metallic-oxide LaNiO3 interface layer via chemical solution deposition in to the Pb(Zr,Ti)O3-film/CoFe2O4-ceramic composites. Further modulation of the magnetoelectric coupling effect could be expected by optimizing the LaNiO3 interface layer, such as thickness, microstructure and orientation. Base on the optimization of the LaNiO3 interface layer, by changing the fabrication process and thickness of the Pb(Zr,Ti)O3 film, the magnetoelectric coupling can be optimized all-roundly due to the different microstructures and Pb(Zr,Ti)O3 to CoFe2O4 ratios. Moreover, the magnetoelectric coupling mechanism, as well as the magnetoelectric coupling dependence on the interface layer, fabrication process, ferroelectric-phase to magnetic-phase ratios and other parameters, would also be explored in such ferroelectric-film/matallic-oxide interface layer/magnetic-ceramic composites. In the frame of "magnetic-mechanical-electric" coupling through the interface between the ferroelectric and magnetic phases, larger magnetoelectric coupling can be obtained via the introduction of metallic-oxide interface layer and the optimization of ferroelectric-phase to magnetic-phase ratios. This would provide detailed insights into the magnetoelectric coupling of ferroelectric-film/magnetic-ceramic composites and offer foundations for the future industrial applications.

磁电复合材料在传感器、换能器等方面具有广阔的应用前景，已成为目前磁电材料领域的一个研究热点。在铁电膜/磁性陶瓷磁电复合材料中，磁性陶瓷的导电性对于复合材料电性能、磁电耦合性能的有效表达具有重要影响。本课题提出以化学溶液沉积法制得的镍酸镧薄膜作为锆钛酸铅膜/钴铁氧体陶瓷复合材料的导电界面层，利用其优良的导电性来保证磁电信号的有效输出。重点研究界面层厚度、微观结构及取向等对磁电性能的调控机理。在界面层优化的前提下，通过改变铁电膜的生长工艺、厚度等参数，利用铁电相微观结构及磁、电两相比例的变化达到复合材料磁电性能的综合优化。深入研究铁电膜/金属氧化物界面层/磁性陶瓷复合材料的磁电耦合机理及其随界面层、制备工艺及两相比例等的变化机制。在铁电、磁性相界面上"磁-力-电"耦合机制框架内，通过金属氧化物界面层及两相比例的调控获得优于目前铁电膜/磁性陶瓷复合材料的磁电耦合系数，为其工业应用奠定基础。

磁电复合材料在传感器、换能器等方面具有广阔的应用前景，已成为目前磁电材料领域的一个研究热点。在铁电膜/磁性陶瓷磁电复合材料中，磁性陶瓷的导电性对于复合材料电性能、磁电耦合性能的有效表达具有重要影响。本课题提出以化学溶液沉积法制得的镍酸镧薄膜作为锆钛酸铅膜/钴铁氧体陶瓷复合材料的导电界面层，利用其优良的导电性来保证磁电信号的有效输出。重点研究界面层厚度、微观结构及取向等对磁电性能的调控机理。在界面层优化的前提下，通过改变锆钛酸铅铁电膜的生长工艺、厚度、取向等参数，利用铁电相微观结构及磁、电两相比例的变化达到复合材料磁电性能的综合优化。实验证明：引入镍酸镧界面层后，因其较低的电阻率使得该体系的铁电性能、压电性能得到显著改善，同时也可将相同工艺条件下的磁电耦合性能提高到155 mV/cm•Oe, 为无镍酸镧界面层复合结构的2.6倍。课题执行过程中，通过前驱体溶液的金属源配制调整锆钛酸铅膜的组分（即Zr:Ti比），通过制备工艺控制锆钛酸铅膜及镍酸镧界面层的厚度，通过引入晶种层控制锆钛酸铅膜的取向等多种手段，以复合结构的磁电、压电和铁电性能为考量，系统研究了铁电膜/金属氧化物界面层/磁性陶瓷复合材料的磁电耦合机理及其随界面层、制备工艺、组分、厚度及取向等的变化机制。在铁电、磁性相界面上“磁-力-电”耦合机制框架内，通过上述参数的调控和优化获得优于目前铁电膜/磁性陶瓷复合材料的磁电耦合系数，为其工业应用奠定基础。