Nano-to-micro spatiotemporal imaging of magnetic skyrmion's life cycle

TL;DR

This study visualizes the entire life cycle of magnetic skyrmions in a defected material using advanced microscopy, revealing their rapid dynamics and potential for high-frequency topological charge manipulation.

Contribution

It introduces a method to track skyrmion dynamics in real-time at nanosecond to microsecond scales, demonstrating their creation, motion, and annihilation processes.

Findings

Skyrmions proliferate within <1 ns after excitation.

Skyrmions contract at 5 ns and drift over microseconds.

Skyrmion dynamics are cyclic at 20 kHz frequency.

Abstract

Magnetic skyrmions are the self-organized topological spin textures behaving like particles. Because of their fast creation and typically long lifetime, experimental verification of skyrmion's creation/annihilation processes has been challenging. Here we successfully track skyrmions dynamics in defect-introduced Co9Zn9Mn2, by using pump-probe Lorentz transmission electron microscope. Following the nanosecond-photothermal excitation, we resolve 160-nm-skyrmion's proliferation at <1 ns, contraction at 5 ns, drift from 10 ns to 4 microsecond and coalescence at 5 microsecond. These motions relay the multiscale arrangement and relaxation of skyrmion clusters in a repeatable cycle of 20 kHz. Such repeatable dynamics of skyrmions, arising from the weakened but still persistent topological protection around defects, enables us to visualize the whole life of the skyrmions, as well as demonstrating the possible high-frequency manipulations of topological charges brought by skyrmions.