Wu Qiong, Ma Xiangyu, Yue Ming, Cong Liying, Ma Zhenhui, Zhang Dongtao, Li Yuqing, Wang Yatao
College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124, China.
ACS Appl Mater Interfaces. 2021 Mar 24;13(11):13548-13555. doi: 10.1021/acsami.0c21669. Epub 2021 Mar 11.
Specially designed SmCo/Co magnetic nanocomposites have been fabricated by a "bottom up" process. SmCo nanochips were first prepared by solution-phase chemical synthesis combined with reductive annealing and then coated by chemical deposition of Co nanorods. Both the SmCo nanochips and Co nanorods are anisotropic and could be simultaneously aligned under the external magnetic field. Magnetic measurements applied on these "bi-anisotropic" SmCo/Co composites show high magnetic performance with the Co phase content in a wide range from 10 to 80 wt %. For the first time ever, the applicable exchange-coupled nanocomposites with a rare-earth content lower than 7 wt % was realized, which exhibits the coercivity close to 10 kOe and remanence 31% larger than that of single phase SmCo. 3-D micromagnetic simulations were performed to reveal that the reversal mechanism in the Co phase was transferred from the incoherent mode to the coherent mode under a tip interface exchange-coupling with a SmCo surface.
通过“自下而上”的工艺制备了特殊设计的SmCo/Co磁性纳米复合材料。首先通过溶液相化学合成结合还原退火制备SmCo纳米芯片，然后通过化学沉积Co纳米棒进行包覆。SmCo纳米芯片和Co纳米棒均为各向异性，并且在外部磁场下能够同时取向。对这些“双各向异性”SmCo/Co复合材料进行的磁性测量表明，在Co相含量为10至80 wt%的宽范围内具有高磁性能。首次实现了稀土含量低于7 wt%的适用交换耦合纳米复合材料，其矫顽力接近10 kOe，剩磁比单相SmCo大31%。进行了三维微磁模拟，以揭示在与SmCo表面的尖端界面交换耦合下，Co相中的反转机制从非相干模式转变为相干模式。
