Calculations of demagnetization curves of Nd-Fe-B magnets based on inhomogeneous nucleation

Demagnetization curves of Nd-Fe-B magnets are evaluated based on the micromagnetics for inhomogeneous nucleation by considering a magnetic planar defect. The inhomogeneous nucleation field, reduced due to the magnetic defect, is increased as an effect of the second anisotropy constant, K₂, even though K₁>4K₂ is satisfied, where K₁ is the first anisotropy constant. Further, the demagnetization process under the condition where the spin structure is conical is also examined in the case of -2K₂<K₁<0. The nucleation field in this case is also reduced due to the defect and is shown to increase as the angle of applied field increases