Recently, observation of new topological magnetic
structures represented by skyrmions is expected to provide new
paths in constructing spintronic devices. In magnetic bubbles,
although these are “ancient” cylinder domains, the type-I bubbles
(renamed as skyrmion bubbles with the same topology as skyrmions)
have remotivated general scientific interests. On using Lorentz
transmission electron microscopy (Lorentz-TEM) to recognize
magnetic bubbles in magnetic nanostructures, scientists observed
some complex vortex-like magnetic structures beyond the traditional
magnetic bubbles, which could be used as information carriers in
emerging spintronic devices. Physical understanding of them,
however, remains unclear. Recently, Tang et al. from High Magnetic
Field Laboratory of Chinese Academy of Sciences clarified these
complex vortex-like structures as depth-modulated three-dimensional
(3-D) magnetic bubbles in a Kagome crystal Fe3Sn2.
