摘要
以软磁性相α-Fe和硬磁性相Nd_2Fe_(14)B为例,研究了软-硬磁性晶粒间的交换耦合相互作用和有效各向异性随晶粒尺寸和软、硬磁性晶粒尺寸比(D_s:D_h)的关系,软-硬磁性晶粒间的有效各向异性常数可以用软、硬磁性相的平均各向异性常数的统计平均值表示,当晶粒尺寸大于其铁磁交换长度时,晶粒分为有、无交换耦合两部分。无交换耦合部分的各向异性常数为通常的K_1,而耦合部分的各向异性常数随到晶粒表面的距离而变化,研究结果表明:软-硬磁性晶粒间的有效各向异性随晶粒尺寸的减小而下降,随着软、硬磁性晶粒尺寸比值(D_s:D_h)的减小而增加。为使软-硬磁性晶粒间的有效各向异性常数K_(eff)保持较高的值,应控制硬磁性晶粒大于35nm,软磁性晶粒尺寸为10nm左右。
Taking α-Fe and Nd2Fe14 B grains as examples, the grain size dependence of effective anisotropy and its variation on the size ratio of magnetically soft and hard grain, Ds : Dh, was investigated. The effective anisotropy constant between magnetically soft and hard grains, Keff, can be expressed as the statistic value of soft and hard grain's anisotropy constants. The grain's anisotropy is divided into coupled and uncoupled parts when grain size D > Lex. The anisotropy constant of uncoupled part is the common value K1 and that of coupled part varies with the distance to the grain surface. The calculation results showed that the exchange-coupling interaction enhances with the reduction of grain size, and the effective anisotropy decreases with reducing the grain size and increasing the ratio of Ds : Dh. In order to get high Keff, the hard grain size should be larger than 35 nm and the soft grain size should be about 10 nm.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2003年第6期561-565,共5页
Chinese Journal of Materials Research
基金
国家八六三计划新材料领域2002AA324050
2002AA302602
山东省自然科学基金Y2000F10
关键词
复合材料
有效各向异性
交换耦合相互作用
软—硬磁性晶粒
矫顽力
composite, effective anisotropy, exchange-coupling interaction, magnetically soft- hard grains, coercivity
