Two-factor analysis of magnetic skyrmions stability in multilayer modified films

The paper studies stable states of magnetic skyrmions arising in magnetically uniaxial nanomodified films, in which the Dzyaloshinskii−Moriya interaction takes place. The influence of defects of the “potential well” type on them is considered, in which the uniaxial anisotropy constant takes smaller but positive values, compared to the value of such in the main film array. The calculation was carried out by the method of micromagnetic modeling (using the open-access software package OOMMF), in which the film (of the Co / Pt type) was taken in the form of a disk, with a defect in its center. It is shown that, depending on the ratio of the Dzyaloshinskii−Moriya interaction parameter and the “potential well” depth, various types of magnetic vortex-like inhomogeneities are stabilized on the defect: kπ-skyrmions (k =1, 2, 3), deformed skyrmion, incomplete skyrmion, etc. It has been established that the type of structure of inhomogeneities, their dimensions and threshold values of the “potential well” depth do not depend on the disk radius and are determined mainly by the value of the anisotropy constant outside the defect. At small values of the latter, magnetic vortices are stabilized in the center of the disk, which change their polarity when the defect is introduced (taken into account). The presence of two factors influencing the stability of vortex-like inhomogeneities in the films under study allows for more flexible control of their statics and dynamics, which creates certain prospects for their use in magnetic memory devices.

1. Ministry of Education and Science of the Russian Federation - State assignment of Russian Federation 075-03- 2024-123/1 15.02.2024