HETEROGENEOUS MAGNETIC STATE OF QUASI-BINARY RARE-EARTH INTERMETALLIC COMPOUNDS WITH CACU5-TYPE AND MGCU2-TYPE STRUCTURES

The magnetic properties of intermetallic R(Co1-xNix)(5), with R = Sm and Gd, and Sm1-xTbxFe0.4Co1.6 compounds have been investigated. The temperature dependence of the ac susceptibility chi has a maximum at some temperature T = T-C(m) (Hopkinson's effect). For binary compounds chi(m) = chi(T-C(m)) = 1/N, where N is the demagnetization factor, and in this case T-C(m) corresponds to the Curie temperature. In quasi-binary compounds (0 < x < 1), chi(m) < (1/N) and chi(m)(H)not equal const, and near T-C(m), chi(T) shows a temperature hysteresis. From the results obtained we conclude that the quasi-binary compounds are magnetically inhomogeneous, probably due to the existence of clusters in which the concentration x differs from stoichiometry.