The paper considers micromagnetic structures arising in a uniaxial disk-shaped ferromagnet containing columnar “potential well” type defect located at its center, within which the material parameters are altered. It was shown that in the disk (in the absence of a defect), \(\:k\pi\:\) -skyrmions ( \(\:k=1,\:2,\dots\:7\) ) are alternately stabilized depending on the defect radius. It was found that in this case, the transformation of the disk’s micromagnetic structure from a state with \(\:k\pi\:\) -skyrmions occurs through the widening of its rings and the formation of a transition region at the disk edge, in which the magnetization vector once again rotates by 180°. Taking into account the presence of the defect, skyrmion stabilization occurs according to a different scenario: the transformation of \(\:k\pi\:\) -skyrmions into \(\:(k+1)\pi\:\) -skyrmions in the central region of the disk, corresponding to the core. In addition, it was found that the critical disk dimensions at which these transformations occur are significantly lower than in the absence of a defect in the disk, which potentially simplifies the production of more complex skyrmions in structure.
