Tang Hao, Mamakhel Mohammad Aref Hasen, Christensen Mogens
Center for Materials Crystallography (CMC), Department of Chemistry, Aarhus University, 8000, Aarhus, Denmark.
Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus, Denmark.
Sci Rep. 2021 Feb 25;11(1):4682. doi: 10.1038/s41598-021-83826-5.
SmCo is one of the most promising candidates for achieving a hard magnet with a high coercivity. Usually, composition, morphology, and size determine the coercivity of a magnet, however, it is challenging to synthesize phase pure SmCo with optimal size and high coercivity. In this paper, we report on the successful synthesis of phase pure SmCo with spherical/prolate spheroids shape. Size control is obtained by utilizing colloidal SiO as a template preventing aggregation and growth of the precursor. The amount of SiO nanoparticles (NPs) in the precursor tunes the average particle size (APS) of the synthesized SmCo with particle dimension from 740 to 504 nm. As-prepared pure SmCo fine powder obtained from using 2 ml SiO suspension possesses an APS of 625 nm and exhibits an excellent coercivity of 2986 kA m (37.5 kOe) without alignment of the particles prior to magnetisation measurements. Comparing with a reference sample prepared without adding any SiO NPs, an enhancement of 35% of the coercivity was achieved. The improvement is due to phase purity, stable single-domain (SSD) size, and shape anisotropy originating from the prolate spheroid particles.
钐钴是实现具有高矫顽力的硬磁体最有前景的候选材料之一。通常，成分、形态和尺寸决定磁体的矫顽力，然而，合成具有最佳尺寸和高矫顽力的相纯钐钴具有挑战性。在本文中，我们报道了成功合成球形/长椭球体形状的相纯钐钴。通过使用胶体二氧化硅作为模板防止前驱体聚集和生长来实现尺寸控制。前驱体中二氧化硅纳米颗粒（NPs）的量调节合成的钐钴的平均粒径（APS），颗粒尺寸从740到504纳米。使用2毫升二氧化硅悬浮液制备的纯钐钴细粉具有625纳米的平均粒径，并且在磁化测量前颗粒未取向的情况下表现出2986千安/米（37.5千奥斯特）的优异矫顽力。与未添加任何二氧化硅纳米颗粒制备的参考样品相比，矫顽力提高了35%。这种改善归因于相纯度、稳定的单畴（SSD）尺寸以及来自长椭球体颗粒的形状各向异性。
