Crystal structure and physical properties of U3T3Sn4 (T = Ni, Cu) single crystals

Heat capacity experiments, crystal structure determination and transmission electron microscopy have been carried out on U3Cu3Sn4 singlecrystals. U3Cu3Sn4 was confirmed to be a heavy-fermion antiferromagnet(T-N = 13(1) K) with a low-temperature electronic heat capacity coefficient gamma = 390 mJ/mol(U)K(2). Low-temperature heat capacity experiments on a U3Ni3Sn4 single-crystal indicate that below 0.4 K there is a crossover between the previously observed non-Fermi-liquid behavior and a Fermi-liquid state.