The skyrmion annihilations induced by local reversal of background field in skyrmion lattice
Abstract The understanding of the creation and annihilation dynamics of a magnetic skyrmion is significant due to its potential applications in information storage and spintronics. Although there have been extensive investigations on the annihilation of isolated skyrmion, topological annihilation in periodic skyrmion lattice is a more complex process. We report a micromagnetic simulation study about the annihilation process of a two-dimensional skyrmion triangular lattice triggered by a uniform field HREV of comparable size to the skyrmion, which is opposite to the direction of the background field, revealing two annihilation modes. When the HREV center is within the range of a skyrmion, the neighboring skyrmions annihilate in situ, while the center is between adjacent skyrmions, anti-skyrmion is induced in the interstitial region. Both mechanisms tend to experience the intermediate topological vortex or antivortex structure, and the spin system undergoes a long period of relaxation to reach a stable state after the topological charge is stabilized. Our results present a local annihilation scheme that is easy to achieve in a 2D skyrmion lattice and highlight the role of interaction between skyrmions in the transformation between different kinds of topological defects.