History-dependent domain and skyrmion formation in 2D van der Waals magnet Fe3GeTe2

TLDR

Two‑dimensional magnets, including Fe3GeTe2, have attracted attention for fundamental low‑dimensional magnetism and spintronic applications, and recent reports have observed magnetic skyrmions in this material. This study aims to systematically investigate the history‑dependent evolution of spin textures in Fe3GeTe2, an area largely unexplored in 2D magnets. Using real‑space imaging and complementary simulations, the authors map thickness‑dependent magnetic phase diagrams of exfoliated Fe3GeTe2 flakes, revealing a history‑dependent emergence of uniformly magnetised, stripe domain, and skyrmion states. The results show that dipolar interactions and temperature‑dependent out‑of‑plane anisotropy selectively stabilise all three states at zero field and a single temperature, while Dzyaloshinskii‑Moriya interaction is required for Néel‑type domain walls, suggesting new opportunities for 2D devices with topological spin textures.

Abstract

The discovery of two-dimensional magnets has initiated a new field of research, exploring both fundamental low-dimensional magnetism, and prospective spintronic applications. Recently, observations of magnetic skyrmions in the 2D ferromagnet Fe3GeTe2 (FGT) have been reported, introducing further application possibilities. However, controlling the exhibited magnetic state requires systematic knowledge of the history-dependence of the spin textures, which remains largely unexplored in 2D magnets. In this work, we utilise real-space imaging, and complementary simulations, to determine and explain the thickness-dependent magnetic phase diagrams of an exfoliated FGT flake, revealing a complex, history-dependent emergence of the uniformly magnetised, stripe domain and skyrmion states. The results show that the interplay of the dominant dipolar interaction and strongly temperature dependent out-of-plane anisotropy energy terms enables the selective stabilisation of all three states at zero field, and at a single temperature, while the Dzyaloshinksii-Moriya interaction must be present to realise the observed Néel-type domain walls. The findings open perspectives for 2D devices incorporating topological spin textures.