SPECIFIC-HEAT OF SOME TRANS-URANIUM INTERMETALLIC COMPOUNDS - SEARCH FOR HEAVY FERMIONS

We measured the low temperature specific heat of single-phase samples of PuRh2 PuGa3 and NpCd11. These materials are candidates for heavy fe rmion behavior based on their structures and, in the case of PuRh2, on other existing measurements such as magnetic susceptibility. We find rather large gamma values for PuGa3 (225 mJ mol(-1) K-2) and PuRh2 (14 5 mJ mol(-1) K-2), while that for NpCd11 (10 mJ mol(-1) K-2) is low en ough to suggest that another channel of behavior (e.g. magnetism) uses up the available f-electron entropy.