硬磁/反铁磁/软磁核壳结构纳米颗粒的可控制备、交换耦合机制和磁性能研究

针对如何同时提高纳米复合永磁材料矫顽力和剩磁的关键科学问题，本项目拟在硬磁软磁双相纳米复合永磁材料中引入反铁磁相，设计和制备单分散硬磁/反铁磁/软磁(或软磁/反铁磁/硬磁)三相核壳结构纳米颗粒，在单个纳米颗粒内部实现对微观结构和不同交换耦合作用的精确控制，利用硬磁软磁交换耦合作用提高材料的剩磁，利用硬磁反铁磁和软磁反铁磁交换耦合作用提高材料的有效磁晶各向异性、矫顽力和剩磁比，从而进一步提高材料的最大磁能积。系统研究核壳纳米颗粒的硬磁相、反铁磁相和软磁相的磁晶各向异性、形状各向异性、尺寸、成分及三相材料的体积比例和界面结构等因素对不同交换耦合作用、矫顽力、剩磁、交换偏置场、最大磁能积、磁畴结构和磁距分布等磁性能的影响规律；结合微磁学模拟，阐明不同交换耦合作用对最大磁能积的调控机制，建立微观结构及不同交换耦合作用与磁性能的依赖关系，为制备具有更高磁能积的三相复合永磁材料提供实验和理论指导。

Aiming at the key scientific problems about how to enhance the coercivity and remanence of nanocomposite permanent materials at the same time, we plan to introduce antiferromagnetic phase into the hard magnetic and soft magnetic biphase nanocomposite permanent materials, design and prepare the monodisperse hard magnetic/antiferromagnetic/soft magnetic (or soft magnetic/antiferromagnetic/hard magnetic) three-phase core/shell structure nanoparticles (NPs) in this project. And the microstructure and different exchange coupling effect in a single NP will be precisely controlled. In order to further improve the maximum magnetic energy product of the material, the hard magnetic and soft magnetic exchange coupling effect will be used to improve the remanence of the material, and the hard magnetic/antiferromagnetic and soft magnetic/antiferromagnetic exchange coupling effects will be used to improve the effective magnetocrystalline anisotropy, coercivity and remanence ratio of the material. The effects of the magnetocrystalline anisotropy, shape anisotropy, size, composition, volume ratio and interface structure of the core/shell NPs on the magnetic properties, such as different exchange coupling, coercivity, remanence, exchange bias field, maximum magnetic energy product, magnetic domain structure and magnetic moment distribution, will be studied. Combined the micromagnetism simulation, the regulation mechanism of different exchange coupling effect on the maximum magnetic energy product will be clarified, and the dependence of microstructure and different exchange coupling effect on magnetic properties will be established. The results will provide experimental and theoretical guidance for preparing three-phase composite permanent materials with higher magnetic energy product.