Skyrmion formation in magnetic thin films and heterostructures

Magnetic skyrmions are small magnetic domains that are topologically non-trivial as shown schematically in Fig. 1. They are characterized by a twist of the magnetization that forms a continuous winding of the magnetization across the domain. The topology is described by a quantized and conserved winding number. The term skyrmion arises from the original work of Skyrme some fifty years ago that described baryons as topological defects of continuous fields. These defects could be considered “protected” because they were characterized by a topological integer that cannot be changed through any continuous deformation of the field. Since then “skyrmion” states have been found in condensed matter systems such as liquid crystals, quantum Hall systems, ferroelectrics, and magnetic materials. The interest in magnetic skyrmions is driven by novel physics and potential applications. The spin texture topology “protects” skyrmions from scattering by structural defects, allowing them to be moved with ~105 times lower current density than a conventional magnetic domain. These features make magnetic skyrmions appealing for low power memory and information processing applications based on spin torque transfer and the topological spin Hall effect. We have ongoing research into the discovery of new magnetic materials hosting skyrmions, the observation of novel properties of skyrmions and the integration into skyrmion-based devices [1-5].