Study of spin-reorientation in Tm2Fe17-xGa x and Sm2Fe17-xGax

In order to compare their anisotropy behavior, Tm₂Fe _17-xGa_x and Sm₂Fe_17-xGa_x (0<x<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⩽T⩽350 K and fields up to 50 kOe. Spin-reorientation behavior was observed in all of the Tm₂ Fe_17-xGa_x samples studied; the nature of the anisotropy depends on both the Ga content and temperature. In Tm₂ Fe_17-xGa_x for x=0, 1, 3 and 5, the anisotropy changes from uniaxial to easy-plane with increasing temperature; while for x=7 and 8, the anisotropy changes from easy-plane to uniaxial. In contrast, none of the Sm₂Fe_17-xGa _x samples studied show spin-reorientation behavior. For Sm ₂Fe_17-xGa_x with x=0, 6, 7, and 8, the anisotropy is easy-plane, while with x=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