Interconnected skyrmions in a nanowire structure: Micromagnetic simulations

Abstract

The magnetization dynamics of two skyrmions with antiparallel vortex rotations on a nanowire substrate were investigated using micromagnetic simulations. When positioned in proximity, the skyrmions exhibit attractive interactions that decrease their separation distance. This interaction leads to a magnetic energy transition, resulting in the fusion of the two skyrmions into a single connected entity. Applying a static magnetic field aligned with the magnetization direction of the skyrmion cores causes this connected structure to expand, increasing the distance between their cores. Conversely, exposing the connected skyrmions to a specific alternating magnetic field induces resonant oscillations in the core-to-core distance, with the resonance frequency decreasing as the field amplitude increases. The effective mass of the connected skyrmions at resonance is calculated using the resonance frequency. Notably, excessively high amplitudes can cause these oscillations to converge the skyrmions excessively, leading to their annihilation. In simulations involving both static and alternating magnetic fields, separation of the connected skyrmions was not observed. These findings have potential implications for the advancement of technologies utilizing skyrmion numbers for innovative applications.