Stabilization and topological transformation of magnetic bubbles in disks of a kagome magnet

Magnetic bubbles are cylinder domains found in a wide variety of uniaxial ferromagnets. They are categorized into two types based on the rotational sense of their domain walls. These two types of bubbles have the potential to be binary states in a skyrmion-bubble-based magnetic memory. Experimental realization of a single bubble along with single bubble transformations in nanostructures is important for single bit operations in such a memory but has not yet been demonstrated. In this study, effects of geometrical confinement on stabilization and transformation of magnetic bubbles in Fe3Sn2 disks were explored. We observed magnetic bubble cluster states with a tunable bubble number based on the disk size and tilted field angle. By tracking the size dependence of the bubble number, we further demonstrate how both types of single bubbles can be realized and transformed into each other in a controlled manner without bubble number variation.