Investigation on magnetic properties and narrow domain wall of Tb2Fe17-xSix single crystals

The magnetic properties and narrow domain are investigated. The substitutio n 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 stren gthened while the Tb-Fe one is slightly weakened by the introduction of sil icon. The anisotropy constants up to the sixth order are calculated by fitt ing the magnetization process of the samples with the different silicon con tents at 1.5 K under the field up to 5.2 x 10(6) A/m. At low temperature, t he intrinsic coercivity has been observed. The domain wall energy and wall thickness were calculated by counting in three anisotropy constants up to t he sixth order and the results indicated that the coercivity is caused by t he typical narrow domain wall pinning-dominated process. The domain wall en ergy and wall thickness were also calculated based on the Egami thermal-act ivation model and the empirical relationship for H-c(T). The mechanism for the intrinsic coercivity was discussed.