Broad microwave absorption bandwidth achieved by exchange coupling interaction between hard and soft magnetic materials

2021 ◽  
Vol 47 (2) ◽  
pp. 2879-2883
Author(s):  
Gang Fang ◽  
Chuyang Liu ◽  
Yun Yang ◽  
Kangsen Peng ◽  
Guoyue Xu ◽  
...  
Keyword(s):  
Magnetic Materials ◽  
Microwave Absorption ◽  
Exchange Coupling ◽  
Soft Magnetic Materials ◽  
Soft Magnetic ◽  
Coupling Interaction ◽  
Absorption Bandwidth ◽  
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.

Hexaferrite/α-iron composite nanowires: Microstructure, exchange-coupling interaction and microwave absorption

2015 ◽  
Vol 621 ◽  
pp. 146-153 ◽  
Author(s):  
Xiangqian Shen ◽  
Fuzhan Song ◽  
Xinchun Yang ◽  
Zhou Wang ◽  
Maoxiang Jing ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Exchange Coupling ◽  
Coupling Interaction ◽  
Exchange Coupling Interaction

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

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.

Preparation and Microwave Absorption Property of the Core-Nanoshell Composite Materials Doped with Nd

2011 ◽  
Vol 335-336 ◽  
pp. 36-39
Author(s):  
Ru Xin Che ◽  
Bing Yu ◽  
Li Qiu Wei
Keyword(s):  
Composite Materials ◽  
Fly Ash ◽  
Microwave Absorption ◽  
Exchange Coupling ◽  
Magnetic Loss ◽  
Microwave Absorption Property ◽  
Absorption Property ◽  
Coupling Interaction ◽  
The Core ◽  
Exchange Coupling Interaction

The core-nanoshell composite materials doped with Nd were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Nd. The thermal decomposition process of the sample was carried out by the thermogravimetry and differential thermal analysis ( TG-DTA ). The morphology and components of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The microwave absorption property was investigated by vector network analyzer ( VNA ). The results indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating. The exchange-coupling interaction enhances magnetic loss of composite materials. So, in the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the core-nanoshell composite absorbers can achieve –31 dB, it is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption.

The exchange coupling interaction in CoFe2O4/Fe3O4 hard and soft magnetic nanocomposites

Vacuum ◽  
2020 ◽  
Vol 181 ◽  
pp. 109751
Author(s):  
Li Wang ◽  
Chaoqun Yang ◽  
Liyue Zhang ◽  
Yue Hu ◽  
Ji Li ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Magnetic Nanocomposites ◽  
Soft Magnetic ◽  
Coupling Interaction ◽  
Exchange Coupling Interaction

Preparation and Microwave Absorption Property of the Core-Nanoshell Composite Materials Doped with Sm

2011 ◽  
Vol 356-360 ◽  
pp. 514-518
Author(s):  
Ru Xin Che ◽  
Bing Yu ◽  
Chun Xia Wang ◽  
Li Qiu Wei
Keyword(s):  
Composite Materials ◽  
Fly Ash ◽  
Microwave Absorption ◽  
Exchange Coupling ◽  
Magnetic Loss ◽  
Microwave Absorption Property ◽  
Absorption Property ◽  
Coupling Interaction ◽  
The Core ◽  
Exchange Coupling Interaction

The core-nanoshell composite materials doped with Sm were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Sm. The thermal decomposition process of the sample was investigated by thermogravimetric analysis-differential scanning calorimetry ( TG- DSC ). The morphology and components of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The microwave absorption property was investigated by vector network analyzer ( VNA ). The results indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating. The exchange-coupling interaction enhances magnetic loss of composite materials. So, in the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the core-nanoshell composite absorbers can achieve –32 dB, it is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption.

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