Topologically protected magnetic structures provide a robust platform for low power consumption devices for computation and data storage. Examples of these structures are skyrmions, chiral domain walls, and spin spirals. Here we use scanning electron microscopy with polarization analysis to unveil the presence of chiral counterclockwise N\'eel spin spirals at the surface of a bulk van der Waals ferromagnet Fe3GeTe2 (FGT), at zero magnetic field. These N\'eel spin spirals survive up to FGT's Curie temperature TC=220K, with little change in the periodicity p=300nm of the spin spiral throughout the studied temperature range. The formation of a spin spiral showing counterclockwise rotation strongly suggests the presence of a positive Dzyaloshinskii-Moriya interaction in FGT, which provides the first steps towards the understanding of the magnetic structure of FGT. Our results additionally pave the way for chiral magnetism in van der Waals materials and their heterostructures.
@article{arxiv.2007.14113,
title = {Chiral Spin Spirals at the Surface of the van der Waals Ferromagnet Fe$_3$GeTe$_2$},
author = {Mariëlle J. Meijer and Juriaan Lucassen and Rembert A. Duine and Henk J. M. Swagten and Bert Koopmans and Reinoud Lavrijsen and Marcos H. D. Guimarães},
journal= {arXiv preprint arXiv:2007.14113},
year = {2020}
}