ANISOTROPIC CHARACTERISTICS OF DEMAGNETIZATION CURVE FOR NANOCRYSTALLINE Nd-Fe-B MAGNET CALCULATED BY MICROMAGNETICS

• 来源期刊: 中国物理(英文版)
• 学科: 物理学
• 关键词: rare-earth Fe compound high coercive force materials magnetization curves hysteresis loop micromagnetism
• 年，卷（期）: 2001,（9）
• 所属期刊栏目: CONDENSED MATTER:STRUCTURE,THERMAL AND MECHANICAL
• 页码范围: 862-868
• 页数: 7页
• 分类号: O4
• 语种: 英文

摘要

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= o∞). Jr/Js is weakly affected by N and the field direction. Jr/Js(N = oo) 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.