Understanding Two-dimensional itinerant ferromagnetism in atomically thin Fe3GeTe2

This study reports the discovery of robust two-dimensional (2D) itinerant ferromagnetism in monolayer Fe₃GeTe₂ (FGT), a van der Waals (vdW) material. The research demonstrates that FGT exhibits strong out-of-plane magnetic anisotropy and remains a ferromagnet even at the monolayer limit. The Curie temperature (T_C) decreases from 207 K in bulk to 130 K in monolayers, indicating a dimensional crossover from 3D to 2D Ising ferromagnetism. For thicker FGT flakes (greater than ~15 nm), a unique magnetic behavior emerges, attributed to the formation of labyrinthine domain patterns. The study also reveals that FGT monolayers exhibit true 2D Ising ferromagnetism, with a critical exponent β consistent with the 2D Ising model. The findings suggest that FGT could be useful for studying controllable 2D itinerant Ising ferromagnetism and for engineering spintronic vdW heterostructures. The research highlights the potential of FGT as a promising candidate for exploring 2D itinerant ferromagnetism and for applications in spintronics.This study reports the discovery of robust two-dimensional (2D) itinerant ferromagnetism in monolayer Fe₃GeTe₂ (FGT), a van der Waals (vdW) material. The research demonstrates that FGT exhibits strong out-of-plane magnetic anisotropy and remains a ferromagnet even at the monolayer limit. The Curie temperature (T_C) decreases from 207 K in bulk to 130 K in monolayers, indicating a dimensional crossover from 3D to 2D Ising ferromagnetism. For thicker FGT flakes (greater than ~15 nm), a unique magnetic behavior emerges, attributed to the formation of labyrinthine domain patterns. The study also reveals that FGT monolayers exhibit true 2D Ising ferromagnetism, with a critical exponent β consistent with the 2D Ising model. The findings suggest that FGT could be useful for studying controllable 2D itinerant Ising ferromagnetism and for engineering spintronic vdW heterostructures. The research highlights the potential of FGT as a promising candidate for exploring 2D itinerant ferromagnetism and for applications in spintronics.

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†‡

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†‡*

| 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†‡