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The magnetic susceptibilities for neodymium, gadolinium and dysprosium germanides and silicides were measured between about 60° to about 700°K. Plots of 1/χ vs T show a Curie-Weiss behavior, but deviations from it are observed below room temperature. The deviations become smaller with decreasing temperature and in most instances tend to approach the asymptote just above the transition temperature. These compounds have the D88 structure and a ferromagnetic spin ordering for rare earth atoms in the crystallographic 6(g) sites, and an antiferromagnetic ordering in the 4(d) sites is consistent with the observed behavior.

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Magnetic behavior of ThCo s , Th,_xYxCos and Th'_xYxCo.Fe has been determined over the temperature range 4 K to the Curie temperature in applied fields up to 120 kOe. Crystal parameters, saturation magnetization and anisotropy fields are presented for ThCo s , for Th,_xYxCos with x = 0.1, 0.2, 0.4, 0.6 and 0.8 and for Th'_xYxCo,Fe with x = 0.2, 0.4, 0.6 and 0.8. ThCo s is observed to be exceptionally hard, not achieving saturation at 120 kOe. Co in this compound exhibits an anomalously low moment, ~ 1.13 fJ-B (as determined at 120 kOe). The Co moment rapidly increases as Y replaces Th in ThCo s , achieving for l\ = 0.2 a value of 1.5 fJ-B' the same as in YCo s . The anisotropy field (H A ) for Th,_xYxCos ternaries at 4.2 K rises from 175 to 203 kOe as x increases from 0 to 0.2 and subsequently falls to 175 kOe for Th 2 YSCo S ' HA increases by 41 kOe between ThCo s and ThCo,Fe. In contrast with the behavior of (Th, Y)Co s ternaries progressive replacement of Th by Y in ThCo,Fe leads to a monatomic decline in H A • Changes of HA by alloying is ascribed to (a) preferential site occupancy or (b) band modification effects and often these cannot be separated. Present results indicate that these two effects are comparable in magnitude.