Bloch Point Structure in a Magnetic Nanosphere

The micromagnetic singularity, the so-called Bloch point, can form a metastable state in the nanosphere. We classify possible types of Bloch points and derive analytically the shape of magnetization distribution inside different Bloch point. We show that external gradient field can stabilize the Bloch point: the shape of the Bloch point becomes radial-dependent one and compute the magnetization structure of the nanosphere, which is in a good agrement with performed spin-lattice simulations.