铌酸锂基高品质磁电复合材料制备及性能调控

在多铁性磁电复合材料领域，发展具有更高磁电耦合系数和磁场灵敏度的材料，对磁电复合材料在磁传感器中的应用非常重要。将具有极高灵敏度的压电传感器与磁性材料结合，将可以用于高灵敏磁信号探测。本项目选择高品质铌酸锂单晶为压电相，利用铌酸锂晶体的高压电系数与介电常数比值、高品质因数和不同切向铌酸锂单晶的多种振动模式，将不同结构取向铌酸锂单晶与磁性相复合。针对不同振动模式设计合理的复合结构，筛选出最优组分、结构及制备工艺，制备具有优异磁电耦合性能且高磁场灵敏度的铌酸锂基磁电复合材料。系统研究铌酸锂单晶不同切向、不同振动模式对复合材料磁电耦合性能的影响和规律，尤其是利用铌酸锂晶体剪切振动模式的耦合机制，为发展基于铌酸锂基磁电复合材料剪切振动模式的磁传感器奠定基础。

The improvement of the materials with higher magnetoelectric (ME) coupling coefficient and magnetic-field sensitivity is a key issue for the application of ME composites as magnetic-field sensors. By combining the magnetic phase (e.g., Metglas) with the piezoelectric sensors with ultra-high sensitivity, the ME composites are capable of detecting very weak magnetic-field. In this project, Lithium niobate (LiNbO3) single crystal, which is widely used as piezoelectric sensor, transdusor, surface acoustic wave device, filter, etc, will be utilized as piezoelectric phase in ME composite, taking the advantages of its high ratio of piezoelectric coefficient to dielectric permitivity, high meachical quality factor (Qm), and multi-mode vibration for differention cutting oritatiations. The appropriate composite structure will be designed for introducing different vibration mode, together with optimized constituent ratio of two phases and fabrication process, in order to achieve the LiNbO3 based ME composite with outstanding ME coupling performance and magnetic-field sensitivity. The dependence of ME properties on the cutting orientation and vibration mode will also be explored systematicly, and the intrinsic mechanism responsible for the ME coupling upon shear-mode vibration of LiNbO3 will be experimentally and theoretically clarified, which would offer scientific basis for the development of ME composites based magnetic-field sensors related to the shear-mode of LiNbO3 that always having high resonance frequency and ultra-high Qm.