Current-Induced Nucleation and Annihilation of Magnetic Skyrmions at Room Temperature in a Chiral Magnet.

A magnetic skyrmion is a nanometer-scale magnetic vortex carrying an integer topological charge. Skyrmions show a promise for potential application in low-power-consumption and high-density memory devices. To promote their use in applications, it is attempted to control the existence of skyrmions using low electric currents at room temperature (RT). This study presents real-space observations for the current-induced formation and annihilation of a skyrmion lattice (SkL) as well as isolated skyrmions in a microdevice composed of a thin chiral magnet Co Zn Mn with a Curie temperature, T ≈ 325 K, above RT. It is found that the critical current for the manipulation of Bloch-type skyrmions is on the order of 10 A m , approximately three orders of magnitude lower than that needed for the creation and drive of ferromagnetic (FM) domain walls in thin FM films. The in situ real-space imaging also demonstrates the dynamical topological transition from a helical or conical structure to a SkL induced by the flow of DC current, thus paving the way for the electrical control of magnetic skyrmions.