Magnetic analysis of Ln(2)M(12)P(7)-type materials (Ln = Ce, Sm, Gd, Er; M= Co, Fe)

A magnetic study has been undertaken on the substances of formula Ln(2)M(12 )X(7). The magnetic susceptibility and the magnetization have been measured as a function of temperature for a constant field. The magnetic susceptibi lity measurements have been performed from ambient temperature up to 1000 K . The effective paramagnetic moments were deduced from 1/chi = f(T) curves, assuming a zero moment on the transition metal atoms. It is shown that the se values are in good agreement with the theoretical values calculated for the free ions Ln(3+). The saturation moment and the paramagnetic Curie temp erature values show an antiferromagnetic behavior for Ce2Co12P7 at low temp erature. The magnetic moment of Sm2Co12P7 measured at 4.2 and 78 K under a 2.66 T magnetic field shows a complex magnetic structure at low temperature . Our work on these materials show that the magnetic properties of Ln(2)M(1 2)X(7) could be interpreted from previous studies on the phases rare earth - transition metal Ln-M.