Coercivity and its dependence on the strength of alignment magnetic field in Nd-Fe-B sintered magnets

The coercivity mechanism of Nd-Fe-B sintered magnets is investigated using a continuously varying model for a single variable K. The results show that the starting field Hs (which includes the critical field H0 and the expanding field He) is greater than the nucleation field Hn and is the main element that controls the coercive force in Nd-Fe-B sintered magnets. The comparison between theory and experiment on the dependence of coercivity on the field strength aligning the grains Ha indicates that the starting field theory is in better agreement with the experimental result than other theories discussed.