BiFeO3基赝三元系陶瓷室温磁电耦合性能调控与机理研究

BiFeO3 is the most representative room-temperature multiferroic materials，which has great application prospects in memory storage and magnetoelectric devices. However, the weak magnetoelectric coupling is the key issue to promote their practical applications. Based on the studies of A/B-substituted BiFeO3 ceramics, this proposal intends to control the magnetoelectric coupling characteristics of BiFeO3-based pseudo-ternary ceramics by A/B sites collaborative replacement. Firstly, the relationship between A/B substitution ratio and the phase transition temperature is established. The improvement of magnetoelectric coupling effect can be realized by controlling the relatively values between Curie temperature and magnetic transition temperature. Then, through the replacement of B-site with magnetic ions, the intrinsic magnetic structure and the magnetoelectric coupling property of BiFeO3-based ceramics can be controlled. Finally, the domain structure of normal ferroelectrics and relaxor ferroelectrics are obtained. The evolution of the domain structure during phase transition from normal ferroelectrics to relaxor ferroelectrics is analyzed, and the influence of domain structure on the coupling mechanism between ferroelectric and magnetic domains would been explored. The implementation of this project will lay the foundation for the application of BiFeO3 multiferroic ceramics and greatly promote the development of multiferroic materials.

BiFeO3是最具代表性的室温多铁性材料，其在新型信息存储及磁电器件等领域具有巨大的应用前景。但是，磁电耦合性能弱是推进其应用化过程中亟待解决的关键科学问题。本项目在BiFeO3陶瓷A/B位置换改性的研究基础上，拟通过A/B位协同置换实现BiFeO3基赝三元系陶瓷磁电耦合性能的调控。首先，建立A/B位置换比例与相变温度变化趋势的关系，通过调控铁电居里温度和磁转变温度的相对高低实现磁电耦合性能的调控。随后，通过B位磁性离子的置换实现BiFeO3陶瓷本征磁结构及磁电耦合性能的调控。最后，获得正常铁电体和弛豫铁电体的畴结构，分析正常铁电体到弛豫铁电体相变过程中畴结构形态的演化规律，揭示畴结构对铁电畴与磁畴耦合机理的影响规律。本项目的实施将为BiFeO3多铁陶瓷的应用奠定基础，且大大促进多铁性材料的发展。

BiFeO3是最典型的单相室温多铁性材料，然而其较差的磁电耦合性能阻碍了应用化进程的发展。离子置换是调控BiFeO3基陶瓷磁电耦合性能的关键。首先，我们制备了系列BiFeO3基三元体系陶瓷，建立了A/B位置换比例与相变温度变化趋势的关系，通过调控铁电居里温度和磁转变温度的相对高低实现磁电耦合性能的调控。随后，研究了磁性离子置换对BiFeO3基陶瓷结构及性能的影响，通过B位磁性离子的置换实现BiFeO3陶瓷本征磁结构及磁电耦合性能的调控，结果表明，磁性离子置换可以改变BiFeO3的磁性能进而影响其磁电耦合性能。最后，研究了系列陶瓷的磁电耦合性能，揭示了结构与磁电耦合性能的影响规律。本项目的研究结果对BiFeO3基陶瓷磁电耦合性能的调控具有重要的意义，同时为BiFeO3陶瓷的应用化进程奠定了理论基础。相关研究工作在本领域国内外期刊上已发表论文12篇。较好的完成了该项目的预期研究任务。

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