Magnetic critical behavior of the van der Waals Fe5GeTe2 crystal with near room temperature ferromagnetism

Zhengxian Li; Wei Xia; Hao Su; Zhenhai Yu; Yunpeng Fu; Leiming Chen; Xia Wang; Na Yu; Zhiqiang Zou; Yanfeng Guo

doi:10.1038/s41598-020-72203-3

Magnetic critical behavior of the van der Waals Fe₅GeTe₂ crystal with near room temperature ferromagnetism

Sci Rep. 2020 Sep 18;10(1):15345. doi: 10.1038/s41598-020-72203-3.

Authors

Zhengxian Li^{1

2

3}, Wei Xia^{1

2

3}, Hao Su^{1

2

3}, Zhenhai Yu¹, Yunpeng Fu¹, Leiming Chen⁴, Xia Wang^{1

5}, Na Yu^{1

5}, Zhiqiang Zou^{1

5}, Yanfeng Guo⁶

Affiliations

¹ School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
² Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.
³ University of Chinese Academy of Sciences, Beijing, 100049, China.
⁴ School of Materials Science and Engineering, Henan Key Laboratory of Aeronautic Materials and Application Technology, Zhengzhou University of Aeronautics, Zhengzhou, 450046, Henan, China. lmchen@zua.edu.cn.
⁵ Analytical Instrumentation Center, School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
⁶ School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China. guoyf@shanghaitech.edu.cn.

Abstract

The van der Waals ferromagnet Fe₅GeTe₂ has a Curie temperature T_C of about 270 K, which is tunable through controlling the Fe deficiency content and can even reach above room temperature. To achieve insights into its ferromagnetic exchange that gives the high T_C, the critical behavior has been investigated by measuring the magnetization in Fe₅GeTe₂ crystal around the ferromagnetic ordering temperature. The analysis of the measured magnetization by using various techniques harmonically reached to a set of reliable critical exponents with T_C = 273.7 K, β = 0.3457 ± 0.001, γ = 1.40617 ± 0.003, and δ = 5.021 ± 0.001. By comparing these critical exponents with those predicted by various models, it seems that the magnetic properties of Fe₅GeTe₂ could be interpreted by a three-dimensional magnetic exchange with the exchange distance decaying as J(r) ≈ r^-4.916, close to that of a three-dimensional Heisenberg model with long-range magnetic coupling.

Abstract

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