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arXiv · 1803.02559

Two-Dimensional Itinerant Ising Ferromagnetism in Atomically thin Fe3GeTe2

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

Recent discoveries of intrinsic two-dimensional (2D) ferromagnetism in insulating/semiconducting van der Waals (vdW) crystals open up new possibilities for studying fundamental 2D magnetism and devices employing localized spins. However, a vdW material that exhibits 2D itinerant magnetism remains elusive. In fact, the synthesis of such single-crystal ferromagnetic metals with strong perpendicular anisotropy at the atomically thin limit has been a long-standing challenge. Here, we demonstrate that monolayer Fe3GeTe2 is a robust 2D itinerant ferromagnet with strong out-of-plane anisotropy. Layer-dependent studies reveal a crossover from 3D to 2D Ising ferromagnetism for thicknesses less than 4 nm (five layers), accompanying a fast drop of the Curie temperature from 207 K down to 130 K in the monolayer. For Fe3GeTe2 flakes thicker than ~15 nm, a peculiar magnetic behavior emerges within an intermediate temperature range, which we show is due to the formation of labyrinthine domain patterns. Our work introduces a novel atomically thin ferromagnetic metal that could be useful for the study of controllable 2D itinerant Ising ferromagnetism and for engineering spintronic vdW heterostructures.

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Zaiyao Fei, Bevin Huang, Paul Malinowski, Wenbo Wang, Tiancheng Song, Joshua Sanchez, Wang Yao, Di Xiao, Xiaoyang Zhu, Andrew May, Weida Wu, David Cobden, Jiun-Haw Chu, Xiaodong Xu. 2018-03-07. Two-Dimensional Itinerant Ising Ferromagnetism in Atomically thin Fe3GeTe2. https://doi.org/10.1038/s41563-018-0149-7

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