Liu Jialing, Wan Si, Li Bo, Li Bailing, Liang Jingyi, Lu Ping, Zhang Zucheng, Li Wei, Li Xin, Huangfu Ying, Wu Ruixia, Song Rong, Yang Xiangdong, Liu Chang, Hong Ruohao, Duan Xiangfeng, Li Jia, Duan Xidong
Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha 410082, China.
Nano Lett. 2024 Mar 27;24(12):3768-3776. doi: 10.1021/acs.nanolett.4c00321. Epub 2024 Mar 13.
The reduced dimensionality and interfacial effects in magnetic nanostructures open the feasibility to tailor magnetic ordering. Here, we report the synthesis of ultrathin metallic CoSi nanoplates with a total thickness that is tunable to 2.2 nm. The interfacial magnetism coupled with the highly anisotropic nanoplate geometry leads to strong perpendicular magnetic anisotropy and robust hard ferromagnetism at room temperature, with a Curie temperature () exceeding 950 K and a coercive field () > 4.0 T at 3 K and 8750 Oe at 300 K. Theoretical calculations suggest that ferromagnetism originates from symmetry breaking and undercoordinated Co atoms at the CoSi and SiO interface. With protection by the self-limiting intrinsic oxide, the interfacial ferromagnetism of the CoSi nanoplates exhibits excellent environmental stability. The controllable growth of ambient stable CoSi nanoplates as 2D hard ferromagnets could open exciting opportunities for fundamental studies and applications in Si-based spintronic devices.
磁性纳米结构中维度的降低和界面效应为定制磁有序提供了可行性。在此，我们报道了超薄金属CoSi纳米片的合成，其总厚度可调节至2.2 nm。界面磁性与高度各向异性的纳米片几何形状相结合，导致在室温下具有强垂直磁各向异性和稳健的硬铁磁性，居里温度（）超过950 K，在3 K时矫顽场（）> 4.0 T，在300 K时为8750 Oe。理论计算表明，铁磁性源于CoSi和SiO界面处的对称性破缺和配位不足的Co原子。在自限性本征氧化物的保护下，CoSi纳米片的界面铁磁性表现出优异的环境稳定性。作为二维硬铁磁体的环境稳定CoSi纳米片的可控生长可为基于硅的自旋电子器件的基础研究和应用带来令人兴奋的机遇。
