Skyrmionic spin structures in layered Fe5GeTe2 up to room temperature

The role of the crystal lattice, temperature and magnetic field for spin structure formation in 2D van der Waals magnet Fe5GeTe2 is a key open question. Using Lorentz transmission electron microscopy, we experimentally observe topological structures up to room metastable pre-cooling stable post-cooling phase Fe5GeTe2. Over wide ranges, skyrmionic bubbles form without preferred chirality, which indicative centrosymmetric structure. In phase, these are observable even application an external field, while transformation from bubble domains stripe seen. To understand order compare macroscopic magnetometry characterization results with microscopic density functional theory calculation. Our show that temperature, can be stabilized magnets.