Specific heat, DC susceptibility, and resistivity measurements on annealed, polycrystalline samples of CeM2Sn2, where M = Ni, Ir, Cu, Rh, Pd, or Pt, indicate that each of these compounds orders antiferromagnetically with transition temperatures ranging from TN = 4.1 to ≈ 0.5 K. All these materials have significant enhancements of the specific heat just before the transition, which can be as large as ∼ 3.5J/mol K2 in some cases. Provided the enhanced heat capacities above TN are associated with large effective (...) masses, the anomalously low ordering temperature and the very large C/T suggest that TN and the Kondo temperature TK are comparable, making these materials particularly attractive for studying the interplay between these competing interactions. The susceptibility for each member of the series except M = Ir follows a Curie-Weiss behavior with a high-temperature effective moment μeff ∼ 2.5μB Ce and a small negative paramagnetic Curie temperature. © 1991. (shrink)

We report specific heat and μSR measurements on Th and/or B substituted UBe13. The specific heat data show that either Th or B substitution reduces the Kondo temperature TK and increases the entropy at the superconducting transition by almost 20%, indicating an enhanced density of states. However, whereas μSR shows clear evidence for magnetic correlations for Th substitutions, no magnetism is observed for B substitutions. The enhanced specific heat jump in the B-substituted material is associated with a change in the (...) superconducting properties as TK is reduced. (shrink)