Analytical and numerical $K_u-B$ phase diagrams for cobalt nanostructures: stability region for a Bloch skyrmion

Abstract

In this letter we calculate the energies corresponding to the different magnetic phases present in a ferromagnetic cylinder by means of analytical calculations. From the comparison of these energies, it is possible to construct magnetic phase diagrams as a function of the uniaxial anisotropy of the sample and the external magnetic field applied. As proof of concept, we analyzed the magnetic phase diagrams for a cobalt dot of 240 nm in diameter and 70 nm in length, with an easy axis parallel to the dot axis, and with a magnetic field applied towards or perpendicular to this axis. From these diagrams we have obtained the stability regions for a Bloch skyrmion (Sk), a vortex core (VC) and a ferromagnetic (F) configuration, which can point in any $\psi$ direction. Our results provide a pathway to engineer the formation and controllability of a skyrmion in a ferromagnetic dot to different anisotropy constants and magnetic fields.

5 pages, 4 figures

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Cited by in corpus (4)

• Forming individual magnetic biskyrmions by merging two skyrmions in a centrosymmetric nanodisk
• Controlling the nucleation and annihilation of skyrmions with magnetostatic interactions
• Surface anisotropy in a magnetic cylinder induced by the displacement of a vortex core
• Distinct magnetic field dependence of Néel skyrmion sizes in ultrathin nanodots