Surface characterization and control of skyrmions in van der Waals ferromagnet Fe₃GaTe₂

Ming-Hsien Hsu^1*, Chak-Ming Liu¹, Po-Wei Chen¹, Neleena Nair G¹, Po-Chun Chang^3,4, Masahiro Haze², Yixi Su³, Yukio Hasegawa², Hsiang-Chih Chiu¹, Wen-Chin Lin¹

¹Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
²Institute for Solid State Physics, the University of Tokyo, Kashiwa, Chiba 277-8581, Japan
³Jülich Centre for Neutron Science at Heinz Maier-Leibnitz-Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
⁴Department of Physics, Tamkang University, New Taipei 25137, Taiwan

* Presenter:Ming-Hsien Hsu, email:dc28773407@gmail.com

Magnetic skyrmions in two-dimensional (2D) van der Waals (vdW) ferromagnets demonstrate potential for high-density and low-energy-consumption spintronic devices. Most of the vdW ferromagnet Curie temperatures are below room temperature (RT). However, Fe₃GaTe₂ (FGT) exhibits high Curie temperature above RT and large perpendicular magnetic anisotropy (PMA). Additionally, controlling skyrmion on vdw ferromagnet is a significant application for spintronic devices. Due to the iron defects within the noncentrosymmetric FGT crystal reveal the spatial inversion symmetry breaking, inducing the emergence of the Dzyaloshinskii−Moriya interaction (DMI) which generates Néel-type skyrmions. In this study, magnetic domains undergo a transition from stripe domains to skyrmions through field cooling. We found two phenomena about skyrmion within field cooling (FC). First, to observe skyrmion generation in FGT using the FC method, FGT was subjected to magnetic domain images at various magnetic fields (0-1000 Oe). As the magnetic field increases, the size of the skyrmion is enlarged, leading to a reduction in the number of skyrmions. Second, the external field was applied and subsequently removed, leading to an increase in bubble domain size at FC. The results demonstrate that when the magnetic field was applied at 5800 Oe, the magnetic domains exhibited deformation. Upon reaching 6400 Oe, the magnetic field caused the magnetic domains to transform into stripe domains. These observations provide valuable insights for future application of 2D magnetic materials.

Keywords: 2D ferromagnet, skyrmion, Dzyaloshinskii−Moriya interaction, room temperature