The Motion Behavior Of Skyrmion Under The Magnetic Field Gradient

For half a century,magnetic storage has become the world's leading data storage medium,and people's lives have changed dramatically.In order to make data storage more efficient,the research of track memory with magnetic domain as the basic magnetic storage unit has been paid more and more attention by researchers.Track memory is a non-volatile information storage device.Since the current controls the movement of the magnetic domain,we can store the required information by storing the data in the form of magnetic domains on the track.Among them,the skyrmion track,which is based on the advantages of non-volatility,high energy efficiency,high storage density and extremely small ohmic heat,has attracted the attention of scholars at home and abroad.However,the ferromagnetic skyrmion has a topological flux,and the topological magnetic flux will cause the skyrmion to be subject to Magnus force,which will cause the skyrmion's motion trajectory to shift and effect the stability of the skyrmion.At the same time,the Joule heat generated by the current driving the skyrmion is likely to make the skyrmion unstable.In order to solve the effects of these factors,we use a gradient magnetic field to drive the skyrmion.In this paper,micro-magnetic simulation software OOMMF(the Object-Oriented Micro Magnetic Framework)is used to calculate the effect of artificially added gradient magnetic field to the nucleation of a single skyrmion in a confined cross nanowire and the motion characteristics of the skyrmion on the nanowire.We find that under the magnetic field gradient,there are breathing patterns and movement patterns in the moving process.This suggests that skyrmion's motion is not only related to the gradient of the magnetic field,but also depends on the Dzyaloshinskii-Moriya interaction.When the magnetic field gradient increases,skyrmion can effectively overcome the skyrmion Hall effect and produce breathing patterns during the movement.By studying magnetic field gradients,we have provided an alternative method to regulate the movement of the skyrmion at micron or nanometer sizes.