Abstract The demagnetization curves for nanocrystalline Nd-Fe-B magnets of a stoichiometric composition were calculated by making use of the finite element technique of micromagnetics. The curve, especially iHc, varies in a wide range with the direction of applied field if the grain number N is taken to be small. With the increase of N, the range becomes smaller and the average of iHc decreases and approaches a limit iHc(N = ∞). iHc for finite N is larger than, or at least equal to, iHc(N = ∞). Jr/Js is weakly affected by N and the field direction. Jr/Js(N = ∞) decreases with the increase of grain size L. These are larger than the experimental values for the Nd-rich Nd2.33Fe14B1.06Si0.21 magnets by ～0.05. iHc(N = ∞) increases with the increase of L, and is close to or somewhat smaller than the experimental values of the Nd-rich magnet, as would be expected. In contrast, the curve calculated for the non-interacting grain system (Stoner-Wohlfarth model) of N ≥ 30 depends neither on the field direction nor on N.
Received: 16 December 2000
Revised: 13 February 2001
Accepted manuscript online:
PACS:
75.60.Ej
(Magnetization curves, hysteresis, Barkhausen and related effects)
Fund: Project supported by the National Natural Science Foundation of China (Grant No. 59871019).
Cite this article:
Jin Han-min (金汉民), Wang Xue-feng (王学凤), Zhao Su-fen (赵素芬), Yan Yu (闫羽) ANISOTROPIC CHARACTERISTICS OF DEMAGNETIZATION CURVE FOR NANOCRYSTALLINE Nd-Fe-B MAGNET CALCULATED BY MICROMAGNETICS 2001 Chinese Physics 10 862
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