Origin of spin reorientation in Nd₂Fe₁₄B permanent magnet

The spin reorientation in Nd₂Fe₁₄B, which is the host crystal of the well-known neodymium permanent magnet, is thought to originate from the crystal field effect and is usually studied by an empirical model with parameters extracted from magnetization data of the experiments. However, in this study, we found, for the first time, that the spin reorientation in Nd₂Fe₁₄B is caused by Dzyaloshinskii–Moriya interactions. Our simulations successfully reproduce the peak-like of magnetic anisotropy energy in the experiment without any empirical parameter. 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 contribute toward the physical properties of magnetic materials.