Dzyaloshinskii–Moriya interactions in Nd2Fe14B as the origin of spin reorientation and the rotating magnetocaloric effect

In this study, the mechanism of spin reorientation in Nd2Fe14B, which is the host crystal of prevalently employed neodymium permanent magnets, was investigated by combining first–principles calculations and Monte Carlo simulations. Spin reorientation is thought to originate from crystal field effects and has not received significant attention from researchers because it is an undesirable property in hard magnet applications. Similarly, Dzyaloshinskii–Moriya interactions are often ignored in rare–earth bulk systems, including permanent magnets such as Nd2Fe14B, because it is believed that magnetic anisotropy is more dominant than Dzyaloshinskii–Moriya interactions. However, in this study, for the first time, we found that the spin reorientation in Nd2Fe14B is caused by Dzyaloshinskii–Moriya interactions. Furthermore, we found that the spin reorientation in Nd2Fe14B results in the rotating magnetocaloric effect, which might be used for practical applications. We also found that the Dzyaloshinskii–Moriya interactions non-negligibly affect the physical properties of magnetic materials.