A new strategy to chemically synthesize exchange-coupled SmCo5/Sm2Co17 nanocomposites by in situ decomposition of SmCox (5 < x < 8.5) is reported in this work. Our synthesis starts with the fabrication of Co/Sm2O3 (Sm to Co atomic ratio of Sm/Co = 1:4.2), which can be reduced into 40-nm SmCo5 single crystal nanoparticles by Ca under the protection of CaO, showing a high coercivity of 2.85 T and saturation magnetization (Ms) of 0.0671 A·m2·g−1. By changing the Sm/Co to 1:4.5, 1:4.8 and 1:5.2, SmCo5/Sm2Co17 nanocomposites with different proportions were acquired using the same process. Owing to the in situ decomposition of SmCox intermediate, the small size (both of their size less than 10 nm) and uniform phase distribution were achieved in our nanocomposites. Thus, the as-prepared nanocomposites display a strong exchange-coupling interaction. As a consequence, SmCo5/Sm2Co17 (Sm/Co = 1:5.2) exhibits a coercivity of 1.23 T and enhanced M7T (magnetization at 7 T) of 0.0812 A·m2·g−1, increasing by 21% than pure SmCo5. Our synthesis provides a new protocol to prepare exchange-coupled high-performance nanocomposites. The exchange-coupled SmCo5/Sm2Co17 nanocomposites with small size (both of their size less than 10 nm) have been chemically synthesized by in situ decomposition of SmCox (5 < x<8.5), which exhibits a coercivity of 1.23 T and enhanced Ms, increasing by 21% than pure SmCo5.

中文翻译：

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化学合成交换耦合 SmCo5/Sm2Co17 纳米复合材料

这项工作报告了一种通过原位分解 SmCox (5 < x < 8.5) 化学合成交换耦合 SmCo5/Sm2Co17 纳米复合材料的新策略。我们的合成开始于制造 Co/Sm2O3（Sm 与 Co 原子比为 Sm/Co = 1:4.2），它可以在 CaO 的保护下被 Ca 还原成 40-nm SmCo5 单晶纳米粒子，显示出高矫顽力2.85 T 和 0.0671 A·m2·g-1 的饱和磁化强度 (Ms)。通过将 Sm/Co 更改为 1:4.5、1:4.8 和 1:5.2，使用相同的工艺获得了不同比例的 SmCo5/Sm2Co17 纳米复合材料。由于 SmCox 中间体的原位分解，我们的纳米复合材料实现了小尺寸（它们的尺寸均小于 10 nm）和均匀的相分布。因此，所制备的纳米复合材料显示出强烈的交换耦合相互作用。因此，SmCo5/Sm2Co17 (Sm/Co = 1:5.2) 表现出 1.23 T 的矫顽力和增强的 M7T（7 T 时的磁化强度）为 0.0812 A·m2·g-1，比​​纯 SmCo5 增加了 21%。我们的合成提供了一种制备交换耦合高性能纳米复合材料的新方案。通过原位分解 SmCox (5 < x < 8.5) 化学合成了小尺寸（均小于 10 nm）的交换耦合 SmCo5/Sm2Co17 纳米复合材料，其矫顽力为 1.23 T 并增强了 Ms，比纯 SmCo5 增加 21%。