Magnetic hard nanobubble: a possible magnetization structure behind the bi-skyrmion

Transport of intensity equation (TIE) has been applied to process the simulated and experimental images of the magnetic hard nanobubbles, which were acquired in the Lorentz transmission electron microscope (LTEM). Systematic studies demonstrated that the processing parameter in TIE can modulate the features of the retrieved magnetization and induce the bi-spiral structures which may be identified as the bi-skyrmions.