Dependence of Effective Anisotropy on Grain Size in Nanocrystalline Nd2Fe14B Hard Magnetic Material
来源期刊:JOURNAL OF RARE EARTHS2005年第1期
论文作者:GAO Ruwei FENG Weicun Sun Guangfei Zhu Minggang HAN Guangbing Li Wei
Key words:metal materials; effective anisotropy; grain size; exchange-coupling interaction; coercivity; rare earths;
Abstract: Taking nanocrystalline Nd2Fe14B as a typical sample, based on Herzer′s random anisotropy theory and the cubic grain model, the partial exchange-coupling interaction model was established and the dependence of effective anisotropy constant Keff on grain size was investigated. Calculation results reveal that the exchange-coupling interaction enhances and the effective anisotropy of material Keff decreases with the reduction of grain size. The variation of Keff is basically the same as that of coercivity. The decrease of effective anisotropy is the main reason of the reduction of coercivity for nanocrystalline Nd2Fe14B permanent magnetic material.
GAO Ruwei1,FENG Weicun1,Sun Guangfei3,Zhu Minggang2,HAN Guangbing1,Li Wei2
(1.School of Physics and Microelectronics, Shandong University, Jinan 250010, China;
2.Division of Functional Materials, Central Iron and Steel Research Institute, Beijing 100081, China;
3.School of Materials Science, University of Science and Technology Beijing, Beijing 100083, China)
Abstract:Taking nanocrystalline Nd2Fe14B as a typical sample, based on Herzer′s random anisotropy theory and the cubic grain model, the partial exchange-coupling interaction model was established and the dependence of effective anisotropy constant Keff on grain size was investigated. Calculation results reveal that the exchange-coupling interaction enhances and the effective anisotropy of material Keff decreases with the reduction of grain size. The variation of Keff is basically the same as that of coercivity. The decrease of effective anisotropy is the main reason of the reduction of coercivity for nanocrystalline Nd2Fe14B permanent magnetic material.
Key words:metal materials; effective anisotropy; grain size; exchange-coupling interaction; coercivity; rare earths;
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