Magnetism in 3d-4f Intermetallic Compounds
The 19th Asian Workshop on First-Principles Electronic Structure Calculations (ASIAN-19)
概要
Large saturation magnetization and magnetocrystalline anisotropy are required for strong permanent magnet compounds. Recently, NdFe12N has been synthesized as a film, followed by a theoretical work. It shows large magnetization and anistropy field superior to those of Nd2Fe14B which is the main phase of the neorymium magnet.
In the present work, we study NdFe11TiX and NdFe12X (X=B,C,N,O,F) by means of density functional theory. We find that magnetism is sensitive to the choice of X. The magnetization is larger for X=N, O, F than for X=B, C, while the crystal-field-parameter A20 suggests that magnetic anisotropy is the strongest for X=N. The change in the magnetization is explained from the filling of the anti-binding state between the Fe-3d and X-2p states. The X element also affects the magnetic exchange coupling between the Fe and Nd sites, which is a key parameter for temperature dependence of the magnetic anisotropy.
