Relationship Between Bulk Coercivity and Coercivity of Surface Layer in Nd-Fe-B-Based Sintered Magnet

摘要

??The bulk coercivity and coercivity of the polished surface layer of a Nd-Fe-B-based sintered magnet were measured systematically in order to discuss the effectiveness of observing the magnetic domain on the surface of the magnet. It was revealed that the bulk coercivity and coercivity of the polished surface layer were in a proportional relationship even though the coercivity of the surface layer was much smaller than the bulk coercivity. This suggests that the magnetization reversal that occurred in the surface layer has a mechanism similar to that inside of the magnet. The relationship between the bulk coercivity and coercivity of the surface layer was not proportional when the degree of alignment decreased, which can be explained by the increase in the local demagnetizing field on the surface of the magnet.