Magnetic Domain Modulation in van der Waals Material Fe₃GaTe₂ via External Magnetic Fields

Ming-Hsien Hsu^1*, Shao-Chuan Chang¹, Adam Novotny^2,3, Gayathree Mohan¹, Yi-Chia Liu¹, Po-Chun Chang^4,5, Yan-Ru Chu¹, Neleena Nair Gopakumar¹, Jindřich Mach^2,3, Miroslav Bartošík^2,3, Yixi Su⁵, Chao-Hung Du⁴, Riku Iimori⁶, Takashi Kimura⁶, Hsiang-Chih Chiu¹, Tomas Šikola^2,3, Wen-Chin Lin¹

¹Department of Physics, National Taiwan Normal University, Taipei, Taiwan
²Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
³Institute of Physical Engineering, Brno University of Technology, Brno, Czech Republic
⁴Department of Physics, Tamkang University, New Taipei City, Taiwan
⁵Jülich Centre for Neutron Science at Heinz Maier-Leibnitz-Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
⁶Department of Physics, Kyushu University, Motooka, Fukuoka, Japan

* 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 (FGaT) exhibits a high Curie temperature above RT and a large perpendicular magnetic anisotropy (PMA). Additionally, controlling skyrmions 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. To observe skyrmion generation in FGT using the FC method, FGT was subjected to magnetic domain images at various magnetic fields. As the magnetic field increases, the size of the skyrmion is enlarged, leading to a reduction in the number density of skyrmions. Applying an external magnetic field can either enlarge or shrink the bubble domains, depending on the direction of the magnetic field. The bubble domain rearranges to a Hexagonal ordering through the magnetic field. Additionally, local areas were mechanically manipulated using atomic force microscopy (AFM) tips. By modulating the van der Waals (vdW) gap, the magnetic interlayer coupling was tuned. These observations provide valuable insights for future applications of 2D magnetic materials.

Keywords: van der Waals ferromagnet, skyrmion, Dzyaloshinskii−Moriya interaction