Theoretical studies of magnetic domain phase diagrams from micromagnetic simulation

A skyrmion is a kind of quasiparticle observed on the surface of a magnetic material, and the topologically protected vortex structure is known to be produced via spintronics. The special properties allow skyrmions to exist in the interface of devices with an ultralow accumulation rate and a high transportation rate. Magnetic domain walls such as the multiple wormhole domain show up from the ground state with different dendritic densities and shapes when the material is stimulated. The Dzyaloshinskii-Moriya interaction (M_s), anisotropy constant (K), and stiffness coefficient (A) are key parameters that affect the magnetic field relative to the representation of the skyrmion. By tuning these parameters, we can adjust the fragmentation of the magnetic domain, the stability, and the radius of the skyrmion. These parameters also modulate characteristics such as the skyrmion number and helicity, which describe the behavior of the spintronic vortex and strongness. This research shows the relation between the parameters and characteristics with the phase diagram and indicates the range of stable skyrmion existence and its size. The higher saturation magnetization M_s and the lower stiffness coefficient A cause the domain wall width to become thicker. Besides, the skyrmion number N decreases with an increase in the skyrmion size until it transforms into a deformed domain.