Observation of skyrmions in zero field in Fe₃GeTe₂/Bi₂Te₃ samples

2D van der Waals magnets are attractive candidate materials for controlling magnetization switching. They are interesting for novel topological states and highly efficient spin-orbit torque (SOT) magnetic switching. In our studies, we used a van der Waals magnet Fe₃GeTe₂ (FGT) that is grown on Bi₂Te₃ by molecular beam epitaxy (MBE) for the integration of 2D magnets with topological insulators. Using a low temperature MFM, we report the observation of skyrmions in zero field in the FGT (20 ML)/Bi₂Te₃(8ML) due to history-dependence of the spin structure.