Recently, the reduced coercivity of sintered Nd-Fe-B magnets was explained by distortion of the Nd-Fe-B region at the grain boundaries using classical molecular dynamics and phenomenological theory regarding magnetoelastic anisotropy. In this paper, we investigate how the deformation of Nd 2Fe14B affects the crystal field parameter A20 of the Nd ions using first-principles calculations. By examining some cases of crystalline deformation, we confirm that the compressive deformation of Nd ions within the c-plane forces A20 to negative values. This is qualitatively consistent with the results of a previous study. However, quantitatively, the first-principles calculation shows that the magnetic anisotropy constant Ku is less sensitive to the distortion of Nd2Fe14B than suggested from the results obtained using classical and phenomenological theories.
ASJC Scopus subject areas
- Physics and Astronomy(all)