摘要
在 Ｔｂ２ Ｆｅ１７ 化合物中用 Ｓｉ 替代 Ｆｅ 观察到晶格参数减小和居里温度升高．平均场理论分析指出， Ｓｉ 对 Ｆｅ 的替代使 Ｆｅ Ｆｅ 间的交换作用明显增强、 Ｔｂ Ｆｅ 间交换作用轻微地减弱．通过拟合 Ｔｂ２ Ｆｅ１７ － ｘ Ｓｉｘ（ ｘ ＝ ００ ，１０ ，２０ ，３０ ，３３） 单晶的磁化曲线，得到了化合物在不同组分和温度下的各向异性常数．在 Ｔｂ２（ Ｆｅ ， Ｓｉ）１７ 单晶的磁化和退磁过程中，观察到 Ｓｉ 替代 Ｆｅ 时引起低温下的本征窄畴壁钉扎和矫顽力增强．计及三个各向异性常数的计算以及用 Ｅｇａｍｉ 热激发模型和 Ｈｃ 与 Ｔ 的经验关系，对畴壁能和畴壁厚度的计算都证明了 Ｓｉ 的替代导致了窄畴壁的存在，分析了它们随成分和温度变化的规律．
The magnetic properties and narrow domain are investigated.The substitution of silicon for iron leads to the reduction of the lattice parameters,and the significant increase of the Curie temperature from 413?K to 526?K.The mean field analysis show that the Fe\|Fe exchange interaction is much strengthened while the Tb\|Fe one is slightly weakened by the introduction of silicon.The anisotropy constants up to the sixth order are calculated by fitting the magnetization process of the samples with the different silicon contents at 1.5?K under the field up to 5.2×10 6?A/m.At low temperature,the intrinsic coercivity has been observed.The domain wall energy and wall thickness were calculated by counting in three anisotropy constants up to the sixth order and the results indicated that the coercivity is caused by the typical narrow domain wall pinning\|dominated process.The domain wall energy and wall thickness were also calculated based on the Egami thermal\|activation model and the empirical relationship for H c( T ).The mechanism for the intrinsic coercivity was discussed. PACC: 7530G; 6150; 8110
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1999年第9期1751-1759,共9页
Acta Physica Sinica
基金
中国科学院留学回国人员择优支持基金
