磁电二维复合陶瓷的微结构调控与磁电耦合效应增强原理及方法

Magnetoelectric two-dimensional composite ceramic plays a unique role in the development of new magnetoelectric function materials and devices as magnetoelectric conversion units. However, the weak polarization response and magnetoelectric conversion coefficient as a consequence of the poor interface strain-mediated effect in two-dimensional composite ceramic limit its performance improvement and application. The current research is inspired to enhance the strain-mediated magnetoelectric coupling by microstructure design and modification. Two-dimensional composite consisting of piezoelectric Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 and magnetostrictive BaFe12O19 is to be designed via a grain size modification and magnetic induced orientation. The effects of grain size, orientation and their correlation effect on magnetostrictive, piezoelectric response and magnetoelectric coupling coefficient of composite ceramics were studied systematically, aiming at clarifying the magneto-electric coupling enhancement effect and its mechanism. An effective unified systematical physical model will be explored to optimize the magnetoelectric coupling effect of composites based on the controllable grain size and ordered microstructure factors. Accordingly, a correlation model between microstructure factors and the magnetoelectric coupling coefficient in composite ceramic is developed. The current study can be helpful to provide theoretical guidance and technical support for the design and fabrication high-performance magnetoelectric functional ceramics.

磁电二维复合陶瓷作为磁电转换单元在磁电功能器件与信息技术领域具有广泛应用前景。但磁电二维复合陶瓷仍存在磁驱动相界面应力耦合弱而导致电极化响应低和磁电耦合系数小的问题，制约了其性能提高与推广应用。针对现有技术主要靠调整材料组分、优化组分含量及改变外场强度等途径而难以进一步提升界面应力耦合增强磁电耦合效应的局限性，本项目采用晶粒尺寸控制和磁场诱导取向的微结构设计与调控方法，以(Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3)/BaFe12O19二维复合陶瓷为研究对象，系统研究微结构要素晶粒尺寸、取向及两者间关联效应对复合陶瓷磁致伸缩性、压电响应及磁电耦合系数的影响规律，探明晶粒尺寸可控、微结构有序的二维复合陶瓷磁电耦合增强效应及作用机制，建立微结构参量与磁电耦合系数的关联模型，形成微结构特征协同调控与磁电耦合效应增强的方法，为进一步提高功能复合陶瓷磁电耦合性能提供理论指导和技术支持。

为突破现有磁电复合陶瓷用调整组分、优化体积含量以及改变外磁场强度等传统途径而难以提升磁电耦合效应的局限性，本项目围绕无铅磁电复合材料微结构设计与磁电耦合性能调控方面开展了深入细致的研究工作，主要涉及微结构要素晶粒尺寸、取向及界面效应对复合材料磁致伸缩性、压电响应、磁电耦合系数以及磁介电性能的影响规律及作用机制。项目主要成果包括：提出了磁致伸缩材料和无铅压电材料微结构可控制备方法，形成了一种液相烧结和晶粒细化相结合的低温叠层共烧制备技术；提出了利用磁场诱导微结构取向增强复合材料磁电耦合效应方法，微结构参量与磁电耦合系数的关联模型；实现了六角铁氧体磁电复合材料界面耦合增强与磁介电性能；提出了界面过渡层增强磁电二维复合材料磁介电响应。相关研究成果在国内外学术期刊上发表论文7篇，申请国家发明专利6项，授权4项。项目为开发基于磁电耦合效应的新型高性能电子材料与器件及其在传感、微纳能源转换与利用等领域的应用研究提供理论指导和技术支持。