Chemically synthesizing exchange-coupled SmCo5/Sm2Co17 nanocomposites

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 (M-s) of 0.0671 A.m(2).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 M-7T(magnetization at 7 T) of 0.0812 A.m(2).g(-1), increasing by 21% than pure SmCo5. Our synthesis provides a new protocol to prepare exchange-coupled high-performance nanocomposites.

Automated summary

A new strategy for chemically synthesizing exchange-coupled SmCo5/Sm2Co17 nanocomposites by in situ decomposition of SmCox is reported, leading to the preparation of nanocomposites with small size, uniform phase distribution, and strong exchange-coupling interaction by adjusting the Sm/Co ratio.