Spin-reorientation transition induced magnetic skyrmion in Nd2Fe14B magnet

Abstract

The easy axis of Nd2Fe14B is known to deviate from the c-axis when the temperature decreases to under the spin reorientation point TSR, 135 K. In this work, magnetic domain evolution in Nd2Fe14B was in situ observed by using Lorentz transmission electron microscopy at variable temperatures and magnetic fields. It appears that most inverse domains shrink to stripes and disappear suddenly to achieve the saturation state under a magnetic field, and the saturation field increases with the decreasing temperature due to the increased anisotropy. Magnetic bubbles with zero topological number are formed at temperatures higher than TSR, whereas magnetic skyrmions are found at temperatures around TSR due to the spin reorientation. The tunable anisotropy and saturation magnetization at TSR are the main causes of forming magnetic skyrmions. This finding exhibits the feasibility of generating skyrmions in the ordinary rare-earth permanent magnetic materials.