Structure, magnetic, and electrical properties of the LnAg(6)In(6) intermetallics (Ln = La, Ce, Pr, and Nd)

Tetragonal LnAg(6)In(6) compounds have been obtained for the first time for Ln = La, Pr, and Nd, CeAg6.4In5.6 has slightly different stoichiometry, an d a Pr compound also exists with this composition. These materials exhibit ThMn12 type structure (14/mmm). LaAg6In6 is diamagnetic whereas other compo unds are paramagnetic following the Curie-Weiss law above 100 K, For parama gnetic compounds the effective magnetic moments are fairly close to free io n values and Weiss constants are very small. NdAg6In6 exhibits in the chi(T ) plot a maximum at 5 K which most probably corresponds to the Neel point, At 1.7 K the magnetization of the paramagnetic samples linearly depends on magnetic field strength up to 5 T, The temperature dependence of the electr ical resistivity, rho(T), suggests a metallic character of all compounds wi thout any indication of superconducting transition. The electrical resistiv ity of PrAg6.4In5.6 is slightly higher than that for PrAg6In6 and it is mos t probably related to some disorder in an occupation of the crystallographi c positions. (C) 1999 Academic Press.