Two-dimensional itinerant ferromagnetism in atomically thin Fe3GeTe2

Zaiyao Fei; Bevin Huang; Paul Malinowski; Wenbo Wang; Tiancheng Song; Joshua Sanchez; Wang Yao; Di Xiao; Xiaoyang Zhu; Andrew F May; Weida Wu; David H Cobden; Jiun-Haw Chu; Xiaodong Xu

doi:10.1038/s41563-018-0149-7

Two-dimensional itinerant ferromagnetism in atomically thin Fe₃GeTe₂

Nat Mater. 2018 Sep;17(9):778-782. doi: 10.1038/s41563-018-0149-7. Epub 2018 Aug 13.

Authors

Zaiyao Fei¹, Bevin Huang¹, Paul Malinowski¹, Wenbo Wang², Tiancheng Song¹, Joshua Sanchez¹, Wang Yao³, Di Xiao⁴, Xiaoyang Zhu⁵, Andrew F May⁶, Weida Wu², David H Cobden¹, Jiun-Haw Chu⁷, Xiaodong Xu^{8

9}

Affiliations

¹ Department of Physics, University of Washington, Seattle, WA, USA.
² Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA.
³ Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China.
⁴ Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA.
⁵ Department of Chemistry, Columbia University, New York, NY, USA.
⁶ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
⁷ Department of Physics, University of Washington, Seattle, WA, USA. jhchu@uw.edu.
⁸ Department of Physics, University of Washington, Seattle, WA, USA. xuxd@uw.edu.
⁹ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. xuxd@uw.edu.

PMID: 30104669
DOI: 10.1038/s41563-018-0149-7

Abstract

Discoveries of intrinsic two-dimensional (2D) ferromagnetism in van der Waals (vdW) crystals provide an interesting arena for studying fundamental 2D magnetism and devices that employ localized spins^1-4. However, an exfoliable vdW material that exhibits intrinsic 2D itinerant magnetism remains elusive. Here we demonstrate that Fe₃GeTe₂ (FGT), an exfoliable vdW magnet, exhibits robust 2D ferromagnetism with strong perpendicular anisotropy when thinned down to a monolayer. Layer-number-dependent studies reveal a crossover from 3D to 2D Ising ferromagnetism for thicknesses less than 4 nm (five layers), accompanied by a fast drop of the Curie temperature (T_C) from 207 K to 130 K in the monolayer. For FGT flakes thicker than ~15 nm, a distinct magnetic behaviour emerges in an intermediate temperature range, which we show is due to the formation of labyrinthine domain patterns. Our work introduces an atomically thin ferromagnetic metal that could be useful for the study of controllable 2D itinerant ferromagnetism and for engineering spintronic vdW heterostructures⁵.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't