Study of Spin - Reorientation in Tm 2 Fe 17 x Ga x and Sm 2 Fe 17 x Ga x

In order to compare their anisotropy behavior, Tm2Fe17 Ga and Sm2Fe17 Ga (0 8) powders were magnetically aligned using either static-field or dynamic-field methods. Magnetization measurements were carried out along both the easy and hard magnetic directions for temperatures 10 350 K and fields up to 50 kOe. Spin-reorientation behavior was observed in all of the Tm2Fe17 Ga samples studied; the nature of the anisotropy depends on both the Ga content and temperature. In Tm2Fe17 Ga for = 0, 1, 3, and 5, the anisotropy changes from uniaxial to easy-plane with increasing temperature; while for = 7 and 8, the anisotropy changes from easy-plane to uniaxial. In contrast, none of the Sm2Fe17 Ga samples studied show spin-reorientation behavior. For Sm2Fe17 Ga with = 0, 6, 7, and 8, the anisotropy is easy-plane, while with = 1, 2, 3, 4, and 5, the anisotropy is uniaxial; the nature of the anisotropy does not change with temperature over the range of measurement. The results are discussed in terms of the effect of Ga substitution on the Tm-sublattice and Sm-sublattice anisotropies.