scholarly journals Exchange-coupling interaction and effective anisotropy of NdFeB nanocomposite permanent magnetic materials

2004 ◽  
Vol 53 (9) ◽  
pp. 3171
Author(s):  
Feng Wei-Cun ◽  
Gao Ru-Wei ◽  
Han Guang-Bing ◽  
Zhu Ming-Gang ◽  
Li Wei
Keyword(s):  
Magnetic Materials ◽  
Exchange Coupling ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Exchange Coupling Interaction

Size-Dependence of Effective Anisotropy and Coercivity in Nanocomposite Permanent Magnetic Materials

2011 ◽  
Vol 217-218 ◽  
pp. 1689-1692
Author(s):  
Jia Jun Guo ◽  
Zhong Wei Wang ◽  
Jian Zhang ◽  
Hong Wei Li ◽  
Xu Zhao ◽  
...  
Keyword(s):  
Grain Size ◽  
Physical Model ◽  
Magnetic Materials ◽  
Exchange Coupling ◽  
Size Dependence ◽  
Strong Dependence ◽  
Statistical Average ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Exchange Coupling Interaction

Take into account different degree of exchange-coupling interaction between soft and hard grains, the effective anisotropy and coercivity in nanocomposite permanent magnetic materials has been investigated by adopting a statistical average physical model. The calculated results show a strong dependence of effective anisotropy and coercivity on the grain size in these materials. Using this model, the serious deterioration of coercivity in experiments especially when the grain size is less then 15nm could be explained in terms of the dramatic drop of the effective anisotropy in nanocomposites.

Exchange-Coupling Interaction and Effective Anisotropy in Two-Phase Nanocomposite Permanent Magnetic Materials

2005 ◽  
Vol 475-479 ◽  
pp. 2173-2176
Author(s):  
L.M. Liu ◽  
Wei Chen ◽  
M.G. Zhu ◽  
L.Y. Nie ◽  
Ai Jun Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Exchange Coupling ◽  
Coupling Model ◽  
Anisotropy Constant ◽  
Two Phase ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Effective Anisotropy Constant ◽  
Calculation Results ◽  
Exchange Coupling Interaction

Using the part exchange-coupling model, the exchange-coupling interaction between magnetically soft and hard grains in Nd2Fe14B/α-Fe nanocomposite and its effect on the effective anisotropy of the material have been investigated. By testing six different functions, series curves of effective anisotropy constant versus the mean grain size were obtained. The calculation results show that the effective anisotropy of the composite increases slightly with decreasing grain size, reaches the maximum at about 23nm, and then decreases abruptly. The calculated curves resemble the experimental results of the coercivity versus grain size in nanocomposite.

Exchange-coupling interaction and effective anisotropy in nanocomposite permanent materials

2002 ◽  
Vol 47 (14) ◽  
pp. 1166-1169 ◽  
Author(s):  
Ruwei Gao ◽  
Weicun Feng ◽  
Wei Chen ◽  
Biao Wang ◽  
Guangbing Han ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Exchange Coupling Interaction

Exchange-coupling interaction, effective anisotropy and coercivity in nanocomposite permanent materials

2003 ◽  
Vol 94 (1) ◽  
pp. 664-668 ◽  
Author(s):  
R. W. Gao ◽  
W. C. Feng ◽  
H. Q. Liu ◽  
B. Wang ◽  
W. Chen ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Exchange Coupling Interaction

EXCHANGE–COUPLING INTERACTION AND EFFECTIVE ANISOTROPY OF Nd2Fe14B/a-Fe/Nd2Fe14B SANDWICH MULTILAYERED THIN FILM

2010 ◽  
Vol 24 (29) ◽  
pp. 5815-5820
Author(s):  
YAN SUN
Keyword(s):  
Thin Film ◽  
Exchange Coupling ◽  
Hard Phase ◽  
Soft Phase ◽  
Effective Anisotropy ◽  
Coupling Interaction ◽  
Multilayered Thin Film ◽  
Phase Layers ◽  
Exchange Coupling Interaction ◽  
The Given

The exchange–coupling interaction between soft and hard phase layers and the effective anisotropy K eff have been investigated by putting forward an expression of anisotropy at grain interface, [Formula: see text], which is suitable for different coupling conditions in multilayered thin film. The results showed when the dimensions of soft and hard phases are the same (described by b), K eff increases first, then decreases, and reaches a maximum at a certain value of b with increasing b. For the given hard phase dimension bh, K eff decreases monotonously with increasing soft phase dimension bs. However, for the given bs, K eff increases monotonously with the increase of bh. When the dimensions of soft and hard phases are the same, the variation of K eff in multilayered thin film is very similar to that of coercivity given by Yang et al. Our results explained the experimental phenomenon better.

scholarly journals Investigation on Domain Pinning Mechanism in Nanometer Hard Magnetic Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Yan Sun ◽  
Qingbao Ni
Keyword(s):  
Magnetic Materials ◽  
Coupling Coefficient ◽  
Exchange Coupling ◽  
Hard Magnetic Materials ◽  
Wall Width ◽  
Pinning Mechanism ◽  
Coupling Interaction ◽  
Control Range ◽  
Exchange Coupling Interaction ◽  
Domain Pinning

The domain pinning mechanism was investigated in nanometer hard magnetic materials. The pinning fields of domain wall at different inhomogeneities were studied respectively. And exchange-coupling coefficient αex was investigated too. The results showed that αex is proportional to the ratio of inhomogeneity thickness ro to wall width δm for narrow inhomogeneity, while it decreases with enhancement of ro/δm for extended inhomogeneity. At a certain value of ro, exchange-coupling coefficient and pinning fields will reach the maximum. Exchange-coupling interaction and pinning fields are greatly influenced by inhomogeneity. Control range of inhomogeneity may obtain higher coercivity.

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