Types of a Magnetic Singularity in an Asymmetric-Shaped Permalloy Disk

Abstract

In a ferromagnetic material, a Bloch point is a zero-dimensional singularity. It plays an important role in the switching of a two-dimensional (2D) magnetic structure such as skyrmion and magnetic vortex. The local topological number of the 2D magnetic structure is changed by the injection of the magnetic singularity. Their type is classified by its topological number and shape of the surrounding magnetic configuration. In this work, we will report the experimental observation of four other energetically equivalent magnetic singularities in an asymmetric-shaped permalloy (Ni80Fe20, Py) disk using the magnetic full-field X-ray microscopy (MTXM). The observed structures were reproduced by the micromagnetic simulation. The observed magnetic singularity is shifted in the left or right direction from the center of the disk. It is originated from the symmetry breaking in the asymmetric Bloch walls near the magnetic singularity, which is induced by the geometrical asymmetry. Through the shift direction of magnetic singularity, the three-dimensional (3D) magnetic configuration can be figured out. In this poster, we will discuss detailed configurations of four other energetically equivalent magnetic singularities with understanding the 3D magnetic configuration surrounding the magnetic singularity.