Magnetocrystalline anisotropy in iron-rich rare-earth intermetallics. A phenomenological approach for the comparison of the overall and Fe sublatticeanisotropies in RE(FeTi)(12), RE2(FeTi)(17) and RE3(FeTi)(29) related compounds (RE = Y, Sm)

The composition and temperature dependence of the anisotropy field have bee n measured in REFe12-xTix, RE2Fe17-xTix and RE(FeTi)(29) compounds with the 3:29 monoclinic cell being formed by the alternate stacking of the tetrago nal 1:12 and hexagonal or rhombohedral 2:17 units (RE = Y, Sm). By using a phenomenological approach it has been possible to interpret the magnetic be haviour observed in the 3:29 phase. It has been evidenced that the Fe aniso tropy, which mainly originates from itinerant 3d electrons, can be describe d as the simple addition of the individual contribution of the constituent 1:12 and 2:17 units. On the other hand in spite of the localized nature of the Sm anisotropy, when the overall (Fe and Sm) anisotropy is considered, t he simple additivity of the individual unit contributions is only qualitati vely fulfilled.