Quasi-static asymmetric magnetization for hemisphere structure

摘要

Understanding the dynamic magnetization for nanoscale structures has been attracting considerable attention; however, it is extremely limited to uncover such a behavior due to the difficulty in experimentally observing the fast magnetization states. Herein, we theoretically demonstrate in-plane magnetization processes of spherical and hemispherical structures with a diameter of 50 nm by using micromagnetic simulation, presenting symmetrical and asymmetrical vortex structures, respectively. It is emphasized that such an asymmetrical vortex structure is only presented in a quasi-static magnetization state when the external field is at nearly 23 mT along with the symmetric axis. This is associated with an instantaneous evolution from the S-shaped vortex to the C-shaped vortex, ascribed to the lower demagnetization energy for the hemisphere structure compared with that for the sphere structure. The present study could thus open up an insight for designing irregular magnetic structures and understanding the nanoscale magnetic behaviors. Published by AIP Publishing.