MAGNETIC COUPLING IN RARE-EARTH COMPOUNDS OF THE TYPE R2NI17

The temperature dependence and the field dependence (up to 35 T) at 4.2K of the magnetization of several compounds of the type R2-xY were studied. The magnetic isotherms at 4.2 K were analyzed with a mean-field model. The magnetic coupling constant JRNi between the moments of the rare-earth (R) and Ni element in the Hamiltonian H = -ΣNi2JRNiSR SNi were compared with the coupling constants derived from a mean-field analysis of the temperature dependence of the magnetization of the R2Ni17 compounds. From a comparison of the magnetic coupling constants found by means of high-field measurements of R2T17 compounds with T∼Ni, Co, Fe it follows that the RT coupling in the Ni compounds is much lower than in the corresponding Co and Fe compounds. © 1990.