Effect of Si addition on the valence state of Ce in CePd<SUB>3</SUB>

It is observed that Si can be added to CePd3, which has the AuCu3 type cubic structure, to form alloys of the type CePd3Six where 0 &#8804; x &#8804; 0.3. Addition of Si preserves the structure but results in an expansion of the cell volume. The expansion is much larger in CePd3 than in LaPd3 for the same silicon concentration. In CePd3, cerium is in a mixed-valent state and its susceptibility tends to a temperature independent value at low temperature. However, as Si is added to CePd3, the susceptibility progressively increases and shows a Curie-Weiss behavior with effective moment close to that of Ce3+ ions. Thus from lattice parameters and susceptibility measurements, it is inferred that Si addition causes a change in the valence of Ce in CePd3 from mixed valent to nearly trivalent