稀土永磁纳米材料:材料设计、化学合成及其磁学性能

Rare Earth-based Permanent Nanomagnets: Materials Design,Chemical Synthesis and Magnetic Properties

随着现代器件微型化、集成化的发展,具有高磁能积和优异稳定性的永磁材料得到了广泛的应用。材料的纳米化及其组装体构建是实现该目标的潜在途径之一。利用硬磁材料高的磁晶各向异性能及软磁材料高的饱和磁化强度,通过构建硬磁-软磁双相耦合磁体,并同时实现硬磁、软磁两相磁反转可有效提高材料的剩磁和饱和磁化强度,进而显著地增加材料的最大磁能积,为设计和制备新一代高性能磁体提供了重要途径。液相化学法在单相永磁纳米颗粒以及双相耦合纳米磁体制备方面均具有独特的优势,在材料尺寸、组成、形貌及性能方面具有良好的可控性,具有重要的应用价值。介绍了单相稀土永磁纳米材料及硬磁-软磁双相耦合纳米磁体的设计、化学合成及其磁学性能的最新研究进展。

With the development of modern technologies in integrated and miniaturized devices, permanent magnets with high energy products and impressive performances are needed. Fabrications and assemblings of nanostructured magnetic materials possess versatile prospects for applications. Next-generation permanent magnets can be fabricated utilizing nano-particles as building blocks by exploiting nanoscale effects, especially by the exchange-coupled nanocomposites. A typical design of the nanocomposites made of fine mixture of magnetically hard and soft nanoparticles needs well-controlled compo- sitions and interfaces, and vigorously enhances the magnetocrystalline anisotropy and the saturation magnetization. Chemi- cal synthetic routes possess characteristic flexibilities on materials design, sizes, morphologies and self-assembled pros- pects. This review reports some representative studies on rare-earth magnetic nanomaterials and proposes some idealized nanocomposites for nanoparticle-based future permanent magnets with enhanced energy products.