Magnetocrystalline anisotropy in iron-rich rare-earth intermetallics.: A phenomenological approach for the comparison of the overall and Fe sublattice anisotropies 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 been 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 tetragonal 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 behaviour observed in the 3:29 phase. It has been evidenced that the Fe anisotropy, which mainly originates from itinerant 3d electrons, can be described 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, the simple additivity of the individual unit contributions is only qualitatively fulfilled.