Numerical Study of Enhanced Coercivity of a Magnetically Hard Grain with Thin Surface Layers Due to Antiferromagnetic Coupling
Numerical Study of Enhanced Coercivity of a Magnetically Hard Grain with Thin Surface Layers Due to Antiferromagnetic Coupling
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反铁磁耦合导致薄表面层硬磁晶粒增强矫顽力的数值研究
DOI：
10.1109/tmag.2012.2201707
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
and T. Yanai
中科院分区：
文献类型：
--
作者：
H. Fukunaga;Y. Yokoi;M. Nakano;and T. Yanai
基于微磁学理论，计算了硬磁颗粒表面覆盖一层薄铁磁层对磁性的影响。反铁磁交换耦合之间的薄铁磁表面层（SF层）和硬颗粒被发现，以防止在硬颗粒的表面处的反向畴的成核，并增加的结晶度。这是有效的硬晶粒与减少磁各向异性层在其表面上的厚度是可比的交换长度。还发现，几纳米的SF层厚度是合适的。模拟的效果与SF层耦合铁磁和反铁磁的硬晶粒。结果表明，平行于硬颗粒易磁化轴的反铁磁耦合SF层可以提高硬颗粒的磁化率。
The effects of a thin ferromagnetic layer covering a magnetically hard grain on the coercivity were calculated based on micromagnetic theory. Antiferromagnetic exchange coupling between this thin ferromagnetic surface layer (SF layer) and the hard grain was found to prevent nucleation of reverse domains at the surface of the hard grain and to increase the coercivity. This was effective for hard grains with a layer of reduced magnetic anisotropy on their surfaces whose thickness is comparable with the exchange length. It was also found that a SF layer thickness of several nanometers is suitable. The effects were simulated for a hard grain with SF layers coupled both ferromagnetically and antiferromagnetically. It was found that the coercivity can be enhanced by antiferromagnetically coupled SF layers lying parallel to the easy magnetization axis of the hard grain.