Effects of shape and number of grains on the demagnetization curve calculated for nanocrystalline Nd2Fe14B magnets

✍ Scribed by Yu Yan; Mingbo Liu; Hanmin Jin; Xuefeng Wang; Xiaobo Du; Feng Su

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 242 KB
• Volume: 364
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.04.023

✦ Synopsis

Demagnetization curves for nanocrystalline Nd 2 Fe 14 B magnets were calculated by using the micromagnetic finiteelement technique. The shape of the grains is either cubic or tetrakaidecahedral. If the grain number N of the magnet is small, the calculated curve, especially that for m 0i H c , strongly depends on the applied field direction. The dispersion ranges of m 0i H c along different field directions and the average of these decrease with an increase of N. Upon increasing N to infinity, the average approaches a limit m 0i H c ðN ¼ 1Þ. The values for m 0i H c ðN ¼ 1Þ are found to differ slightly for grains of different shapes. When the grain size is small, the values of m 0i H c ðN ¼ 1Þ coincide well with the experimental values for Nd 2.33 Fe 14 B 1.06 Si 0.21 magnets with the same grain size with very thin grain boundary phase. Compared with the effects of grain number and the field direction, the effects of the grain shape are small.