Gao Zhansheng, Xin Baojuan, Chen Jiabiao, Liu Zhaochao, Yao Rui, Ai Wei, He Yuyu, Xu Lingyun, Cheng Tong-Huai, Wang Wei-Hua, Luo Feng
Center for the Physics of Low-Dimensional Materials, Henan Joint International Research Laboratory of New Energy Materials and Devices, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China.
ACS Nano. 2024 Jan 9;18(1):703-712. doi: 10.1021/acsnano.3c08998. Epub 2023 Dec 22.
Two-dimensional ferromagnetic materials (2D-FMs) are expected to become ideal candidates for low-power, high-density information storage in next-generation spintronics devices due to their atomically ultrathin and intriguing magnetic properties. However, 2D-FMs with room-temperature Curie temperatures () are still rarely reported, which greatly hinders their research progress and practical applications. Herein, ultrathin Cu-doped CrTe FMs were successfully prepared and can achieve above-room-temperature ferromagnetism with perpendicular magnetic anisotropy via a facile chemical vapor deposition (CVD) method, which can be controlled down to an atomic thin layer of ∼3.4 nm. STEM-EDX quantitative analysis shows that the proportion of Cu to metal atoms is ∼5%. Moreover, based on the anomalous Hall effect (AHE) measurements in a six-terminal Hall bar device without any encapsulation as well as an out-of-plane magnetic field, the maximum achieved ∼315 K when the thickness of the sample is ∼28.8 nm; even the ultrathin 7.6 nm sample possessed a near-room-temperature of ∼275 K. Meanwhile, theoretical calculations elucidated the mechanism of the ferromagnetic enhancement of Cu-doped CrTe nanosheets. More importantly, the ferromagnetism of CVD-synthesized Cu-doped CrSe nanosheets can also be maintained above room temperature. Our work broadens the scope on room-temperature ferromagnets and their heterojunctions, promoting fundamental research and practical applications in next-generation spintronics.
二维铁磁材料（2D-FMs）由于其原子级超薄且引人入胜的磁性能，有望成为下一代自旋电子器件中低功耗、高密度信息存储的理想候选材料。然而，具有室温居里温度（）的二维铁磁材料仍然鲜有报道，这极大地阻碍了它们的研究进展和实际应用。在此，通过简便的化学气相沉积（CVD）方法成功制备了超薄的铜掺杂CrTe铁磁材料，其能够通过垂直磁各向异性实现高于室温的铁磁性，并且可以控制到约3.4 nm的原子薄层。STEM-EDX定量分析表明，铜与金属原子的比例约为5%。此外，基于在没有任何封装以及面外磁场的六端霍尔条形器件中的反常霍尔效应（AHE）测量，当样品厚度约为28.8 nm时，最大居里温度达到约315 K；即使是7.6 nm的超薄样品也具有约275 K的近室温居里温度。同时，理论计算阐明了铜掺杂CrTe纳米片铁磁增强的机制。更重要的是，CVD合成的铜掺杂CrSe纳米片的铁磁性也可以在室温以上保持。我们的工作拓宽了室温铁磁体及其异质结的研究范围，推动了下一代自旋电子学的基础研究和实际应用。
