Research progress on high performance Nd-Fe-B permanent magnet

摘要

We have systemically investigated the correlations among magnetic characterization and lattice distortion as well as multiphase couplings during the fabrication process of the high performance Nd-Fe-B magnets. Rietveld structural refinement is employed to determine the atomic occupations in every phase in Nd-Fe-B magnet. The magnetism of Nd-Fe-B was studied with a modified magnetic valence model. It reveals that the magnetic moment only depends on the total number of d and s-p as well as f electrons, not on the band shape. The coercivity of Nd-Fe-B magnet is related to the Nd-Fe coupling, and its hard magnetic characteristics is derived from the Nd-B layers. The extra Nd atoms are necessary to be arranged near to the Fe-Fe layers or Fe atomic clusters for forming Nd-Fe pairs, which enhances the coercivity.