Abstract Magnetic nanocomposite material has been widely focused for the potential to become the next generation of magnetic material. In this paper, two kinds of chemical coating methods were used to prepare SmCo 5 /Co nanocomposite particles which were further characterized and compared. The two methods were carried out by using different materials and at different temperatures. In Method I, oleylamine (OAm), oleic acid and Ca(acac) 2 were used and the reaction was carried out at the temperature of 300 °C. In Method II, anhydrous isopropanol, polyvinylpyrrolidone (PVP), N 2 H 4 ·H 2 O and CoCl 2 ·6H 2 O were used and the reaction temperature was ~ 55 °C. It was found that by using the two methods, the growth and the crystal structure of the Co nanoparticles (NPs) are different. In Method I, epitaxial growth on the surface of SmCo 5 NPs was observed and the Co NPs were in a face-centered close packing crystal structure. While in Method II, the coated Co NPs were self-nucleated with a crystal structure of hexagonal close packing. Using Method II with the addition of surfactant, anisotropic nanocomposite particles were achieved with an enhanced saturated magnetization of 84.2 A·m 2 ·kg −1 . And the coercivity change of the NPs illustrates that a nonmagnetic interlayer between the hard and soft magnetic phase is beneficial to maintain the coercivity. Graphic abstract

中文翻译：

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SmCo5/Co磁性纳米复合颗粒的化学合成与表征

摘要 磁性纳米复合材料因其成为下一代磁性材料的潜力而受到广泛关注。本文采用两种化学包覆方法制备了SmCo 5 /Co纳米复合颗粒，并对其进行了进一步表征和比较。这两种方法是通过使用不同的材料和在不同的温度下进行的。在方法I中，使用油胺(OAm)、油酸和Ca(acac) 2 并且反应在300℃的温度下进行。在方法II中，使用无水异丙醇、聚乙烯吡咯烷酮(PVP)、N 2 H 4 ·H 2 O和CoCl 2 ·6H 2 O，反应温度为～55℃。发现通过使用这两种方法，Co纳米颗粒（NPs）的生长和晶体结构是不同的。在方法一中，观察到 SmCo 5 NPs 表面外延生长，Co NPs 呈面心密堆积晶体结构。而在方法II中，涂覆的Co NPs自成核，具有六方密堆积的晶体结构。使用添加表面活性剂的方法II，获得具有84.2 A·m 2 ·kg -1 增强的饱和磁化强度的各向异性纳米复合颗粒。NPs 的矫顽力变化说明硬磁相和软磁相之间的非磁性夹层有利于保持矫顽力。图形摘要 以84.2 A·m 2 ·kg -1 的增强的饱和磁化强度获得各向异性纳米复合颗粒。NPs 的矫顽力变化说明硬磁相和软磁相之间的非磁性夹层有利于保持矫顽力。图形摘要 以84.2 A·m 2 ·kg -1 的增强的饱和磁化强度获得各向异性纳米复合颗粒。NPs 的矫顽力变化说明硬磁相和软磁相之间的非磁性夹层有利于保持矫顽力。图形摘要