Strong intrinsic room-temperature ferromagnetism in freestanding non-van der Waals ultrathin 2D crystals

Hao Wu; Wenfeng Zhang; Li Yang; Jun Wang; Jie Li; Luying Li; Yihua Gao; Liang Zhang; Juan Du; Haibo Shu; Haixin Chang

doi:10.1038/s41467-021-26009-0

Strong intrinsic room-temperature ferromagnetism in freestanding non-van der Waals ultrathin 2D crystals

Nat Commun. 2021 Sep 28;12(1):5688. doi: 10.1038/s41467-021-26009-0.

Authors

Hao Wu¹, Wenfeng Zhang¹, Li Yang¹, Jun Wang², Jie Li¹, Luying Li³, Yihua Gao^{3

4}, Liang Zhang⁵, Juan Du^{6

7}, Haibo Shu², Haixin Chang^{8

9

10}

Affiliations

¹ Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China.
² College of Optical and Electronic Technology, China Jiliang University, Hangzhou, 310018, China.
³ Center for Nanoscale Characterization and Devices, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁴ School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁵ School of Science and Center for Materials Science and Engineering, School of Microelectronics and Materials Engineering, Guangxi University of Science and Technology, Liuzhou, China.
⁶ Ningbo Institute of Material Technology & Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
⁷ Institute of Materials, Shanghai University, Shanghai, 200444, China.
⁸ Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China. hxchang@hust.edu.cn.
⁹ School of Science and Center for Materials Science and Engineering, School of Microelectronics and Materials Engineering, Guangxi University of Science and Technology, Liuzhou, China. hxchang@hust.edu.cn.
¹⁰ Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China. hxchang@hust.edu.cn.

Abstract

Control of ferromagnetism is of critical importance for a variety of proposed spintronic and topological quantum technologies. Inducing long-range ferromagnetic order in ultrathin 2D crystals will provide more functional possibility to combine their unique electronic, optical and mechanical properties to develop new multifunctional coupled applications. Recently discovered intrinsic 2D ferromagnetic crystals such as Cr₂Ge₂Te₆, CrI₃ and Fe₃GeTe₂ are intrinsically ferromagnetic only below room temperature, mostly far below room temperature (Curie temperature, ~20-207 K). Here we develop a scalable method to prepare freestanding non-van der Waals ultrathin 2D crystals down to mono- and few unit cells (UC) and report unexpected strong, intrinsic, ambient-air-robust, room-temperature ferromagnetism with T_C up to ~367 K in freestanding non-van der Waals 2D CrTe crystals. Freestanding 2D CrTe crystals show comparable or better ferromagnetic properties to widely-used Fe, Co, Ni and BaFe₁₂O₁₉, promising as new platforms for room-temperature intrinsically-ferromagnetic 2D crystals and integrated 2D devices.

Grants and funding

2016YFB0700702/Ministry of Science and Technology of the People's Republic of China (Chinese Ministry of Science and Technology)