Effective Anisotropy in Magnetically Nd2Fe14B/α-Fe Nanocomposite
GUO Jia-Jun1, CHEN Lei2, ZHAO Xu1, FAN Su-Li1, CHEN Wei1
1Department of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Shijiazhuang 050016 2Physics Teaching Office, Beijing Jiaotong University Haibin College, Huanghua 061100
Effective Anisotropy in Magnetically Nd2Fe14B/α-Fe Nanocomposite
GUO Jia-Jun1, CHEN Lei2, ZHAO Xu1, FAN Su-Li1, CHEN Wei1
1Department of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Shijiazhuang 050016 2Physics Teaching Office, Beijing Jiaotong University Haibin College, Huanghua 061100
摘要Considering different contact situations of grains, we investigate the effects of exchange-coupling interaction on effective anisotropies of magnetically soft α-Fe grains, hard Nd2Fe14B grains and Nd2Fe14B/α-Fe nanocomposite. An expression of effective anisotropy suitable for different degrees of exchange-coupling between grains is presented. The calculation results show that the exchange-coupling interaction increases the average anisotropy of soft grains and decreases that of hard grains. The effective anisotropy of Nd2Fe14B/α-Fe nanocomposite decreases smoothly with decreasing grain size when the grain size is larger than 20 nm while it decreases dramatically with further decrease of the grain size. In order to maintain high coercivity in Nd2Fe14B/α-Fe nanocomposite, the grain size should not be less than 20nm.
Abstract：Considering different contact situations of grains, we investigate the effects of exchange-coupling interaction on effective anisotropies of magnetically soft α-Fe grains, hard Nd2Fe14B grains and Nd2Fe14B/α-Fe nanocomposite. An expression of effective anisotropy suitable for different degrees of exchange-coupling between grains is presented. The calculation results show that the exchange-coupling interaction increases the average anisotropy of soft grains and decreases that of hard grains. The effective anisotropy of Nd2Fe14B/α-Fe nanocomposite decreases smoothly with decreasing grain size when the grain size is larger than 20 nm while it decreases dramatically with further decrease of the grain size. In order to maintain high coercivity in Nd2Fe14B/α-Fe nanocomposite, the grain size should not be less than 20nm.
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2010, Vol. 27 
