Intermetallic compounds of rare earth elements and Ni, Co, or Fe

A survey is given of the composition and crystal structure of existing rare earth transition intermetallics. The relationship in crystal structure of the compounds RM2, RM3, R2M7, RM5, and R2M17 is briefly discussed (R and M represent a rare earth and 3d element, respectively). The variation of the magnetic moment of the M atoms and the variation of the Curie temperature brought about by the increase of the molar fraction of the rare earth element in the various compounds is different for M being Ni, Co, or Fe. An attempt has been made to explain these differences by means of Friedel's model of d-bands in transition metals. The R–M spin interaction is antiferromagnetic and leads in general to compensation points in the magnetization versus temperature curves. It is shown that these compensation points should vary with R as g (g − 1) J (J + 1). This relation is obeyed for the compounds RFe3 for which magnetic data and the lattice constants are given. A mechanism for the R–M exchange interaction is proposed. Magnetic data are also given for the compounds GdGa and GdGa0.7Cu0.3 isostructural with GdNi.