Enhancement of exchange coupling and hard magnetic properties in nanocomposites by magnetic annealing
Enhancement of exchange coupling and hard magnetic properties in nanocomposites by magnetic annealing
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DOI：
10.1016/j.actamat.2005.05.015
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发表时间：
2005-09-01
期刊：
影响因子：
9.4
通讯作者：
Liu, JP
中科院分区：
文献类型：
--
作者：
Cui, BZ;Han, K;Liu, JP
通过磁性退火优化Nd2Fe14B/ α - fe型纳米复合材料的纳米结构，提高了材料的交换耦合性能和硬磁性能。相比Nd2.4Pr5.6Dy1Fe84Mo1B6样品退火没有磁场,磁场退火导致明显提高矫顽力设定h (c),剩余4π先生,和能源产品(BH) (max)中心圆点(BH) (max) 50 K增强43.7%经过退火在磁场的19个t扭结的退磁曲线消失了,另外,一个更好的方形的退磁曲线观察磁性退火样品。用汉高图评价颗粒间交换耦合。磁性退火后的样品中存在更强的晶间交换耦合，这是由于磁性退火促进了纳米结构的细化。通过x射线衍射、透射电子显微镜、低温退磁曲线和改进的布朗方程分析证实了纳米结构的细化。磁退火后样品的硬磁性能的改善主要来自于磁场诱导的交换耦合增强。(c) 2005材料学报Elsevier Ltd.出版。版权所有。
An enhancement of the exchange coupling and hard magnetic properties of melt-spun Nd2Fe14B/alpha-Fe-type nanocomposites was achieved by optimization of their nanostructured morphology via magnetic annealing. Compared with the Nd2.4Pr5.6Dy1Fe84Mo1B6 sample annealed without a magnetic field, the magnetic annealing results in a noticeable improvement in the coercivity H-i(c), the remanence 4 pi Mr, and energy product (BH)(max)center dot (BH)(max) at 50 K was enhanced by 43.7% after magnetic annealing in a field of 19 T. The kink in the demagnetization curve disappeared and, additionally, a much better squareness of the demagnetization curves was observed in the magnetically annealed samples. The intergrain exchange coupling was evaluated by Henkel plots. Evidence for stronger intergrain exchange coupling was found in the magnetically annealed sample, which is due to nanostructure refinement promoted by the magnetic annealing. The nanostructure refinement was confirmed by X-ray diffraction, transmission electron microscope, low-temperature demagnetization curves and a modified Brown's equation analysis. The improvement of hard magnetic properties of the magnetically annealed sample results mainly from the magnetic-field-induced exchange-coupling enhancement. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.