CAJ | 학술논문

以软磁性相α-Fe和硬磁性相Nd2Fe14B为例,研究了软、硬磁性晶粒间的交换耦合作用和有效各向异性常数<Ksh>随晶粒尺寸的变化关系.由于晶粒间的交换耦合作用,晶粒可分为晶粒内部无界面交换耦合作用影响和晶粒表面有界面交换耦合作用影响两部分,其各向异性常数为两部分的统计平均值.计算结果表明:对固定的软磁性晶粒尺寸Ds, <Ksh>随硬磁性晶粒尺寸Dh一致增加;对固定的Dh, <Ksh>随Ds一致减小.为使软、硬磁性晶粒间的有效各向异性常数Keff 保持较高的值,应控制硬磁性晶粒大于35 nm,软磁性晶粒在10 nm 左右.
이연자성상α-Fe화경자성상Nd2Fe14B위례,연구료연、경자성정립간적교환우합작용화유효각향이성상수<Ksh>수정립척촌적변화관계.유우정립간적교환우합작용,정립가분위정립내부무계면교환우합작용영향화정립표면유계면교환우합작용영향량부분,기각향이성상수위량부분적통계평균치.계산결과표명:대고정적연자성정립척촌Ds, <Ksh>수경자성정립척촌Dh일치증가;대고정적Dh, <Ksh>수Ds일치감소.위사연、경자성정립간적유효각향이성상수Keff 보지교고적치,응공제경자성정립대우35 nm,연자성정립재10 nm 좌우.
The effects of grain size on the effective anisotropy constant <Ksh> between the exchange-coupled magnetically soft (α-Fe) and hard (Nd2Fe14B) nano-grains were investigated. Considering the existence of the interfacial exchange coupling between grains, the grain can be divided into two parts: inner part without interfacial exchange-coupling effects (uncoupled) and interfacial part with interfacial exchange coupling effects (coupled). For the given soft grain size Ds, <Ksh> increases with the increasing hard grain size Dh, and then approaches the magnetic anisotropy of the hard phase. For the given Dh, <Ksh> increases with decreasing Ds. A large <Keff> is predicted in nanocomposite for the hard grain size larger than 35 nm and the soft grain size about 10 nm.