Magnetic bubbles and domain walls in Fe₂GeTe₃

Hung-Hsiang Yang^1*, Namrata Bansal¹, Amir-Abbas Haghighirad², Matthieu Le Tacon², Wulf Wulfhekel¹

¹Physical Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
²Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Karlsruhe, Germany

* Presenter:Hung-Hsiang Yang, email:hung-hsiang.yang@kit.edu

Two-dimensional (2D) magnets have attracted attention due to their potential for applications in the field of spintronics. Among the 2D magnets, Fe2GeTe3 (FGT) is intriguing because it is a ferromagnetic van der Waals semimetal, which has a relatively high ferromagnetic transition temperature of 205 K. [1] In this presentation, we report a recent investigation on FGT using low temperature (0.7 K) scanning tunneling microscopy. In this study, we performed out-of-plane magnetic imaging on the FGT surface using the Cr-coated W tip. As a result, we found that the magnetic bubble transitioned from elliptical to a circular shape in out-of-plane magnetic fields and finally collapsed at 0.32 T. Domain wall widths were extracted from the profiles from the differential tunneling conductance maps containing the information of the exchange stiffness and anisotropy constant of FGT.

[1] G. D. Nguyen et al., Phys. Rev. B, 97, 014425 (2018)

Keywords: spin-polarized scanning tunneling microscopy, two-dimensional magnets, domain walls