skyrmionien

Skyrmionien, in some languages the plural form of skyrmion, refer to nanoscale magnetic skyrmions—topologically nontrivial spin textures that can arise in magnetic materials. A skyrmionien consists of spins arranged so that the magnetization wraps around a sphere by 360 degrees, giving a conserved topological charge known as the skyrmion number or Pontryagin index. This topology imparts stability against continuous deformations and makes skyrmions distinct from ordinary magnetic domains.

Most skyrmionien are stabilized by a combination of exchange interactions, the Dzyaloshinskii-Moriya interaction (DMI) due to broken inversion symmetry, magnetic anisotropy, and external magnetic fields. Depending on the type of rotation of spins in the plane, they can be classified as Bloch-type or Néel-type. Typical diameters range from a few to a few hundred nanometers, and they can persist up to room temperature in certain materials and thin films.

Skyrmionien have been observed in chiral magnets such as MnSi and FeGe and in engineered multilayers and ultrathin films that exhibit interfacial DMI (for example Pt/Co/oxide systems). Their small size and low depinning current make them attractive for information storage and processing.

Manipulation is achieved using electric currents, spin-orbit torques, magnetic fields, or temperature changes. Their motion can be driven by modest current densities and shows unique transport signatures, including a topological Hall effect.

Detection and imaging employ techniques such as Lorentz transmission electron microscopy, spin-polarized scanning probe methods, and magnetic force microscopy. Research aims to develop robust, scalable devices such as racetrack memories that store data in skyrmionien lines.