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

Demagnetization curves of Nd-Fe-B magnets are evaluated being 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 by letting -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 goes up