Speaker
Description
In extremely thin ferromagnetic films, an additional interaction, the so-called Dzyaloshinskii-Moriya interaction (DMI), arises in the micromagnetic energy along with a magnetocrystalline anisotropy favoring the magnetization to be out-of-plane. In such materials, topologically nontrivial, point-like configurations of the magnetization called magnetic skyrmions are observed, which are of great interest in the physics community due to possible applications in high-density data storage. Typically thought of as stabilized by DMI, it has been demonstrated that they may also arise due to stray field effects. For sufficiently thin films, we will characterize skyrmions as local minimizers of a 2D micromagnetic energy augmented by DMI and describe their asymptotics in the regime of dominating exchange (or Dirichlet) energy. In this regime, skyrmions collapse into a point and quantitative rigidity estimates for such maps are required to capture the asymptotics. However, the skyrmions might become smaller than the film thickness, indicating a breakdown of the 2D model. We will present a more carefully obtained thin film model and investigate the question of (non-)existence of stray-field stabilized skyrmions.
