SUPERCONDUCTING AND MAGNETIC-PROPERTIES OF THE HEAVY-FERMION COMPOUNDS UT2AL3(T=NI,PD)

The resistive upper critical field H(c2) as a function of temperature T has been determined for polycrystalline specimens of the isostructural antiferromagnetic heavy-fermion superconductors UT2Al3 (T = Ni, Pd). The zero-temperature superconducting coherence lengths xi0 = 190 angstrom (77 angstrom) for T = Ni (Pd) have been estimated from the initial slope of H(c2)(T), and analyses of previously reported specific-heat data yield an effective mass enhancement m*/m(e) is similar to 40 (49) for T = Ni (Pd), where m(e) is the free-electron mass. High-precision measurements of the normal-state electrical resistivity reveal a broad anomaly below 4.6 K in UNi2Al3, Which correlates with the onset of U-moment antiferromagnetic ordering. In UPd2Al3, the large electrical resistivity drop between T(c), and T(N) almost-equal-to 15 K can be accurately described by an expression that is appropriate for an antiferromagnet with an energy gap DELTA almost-equal-to 40 K and an additional T2 term reflecting Fermi-liquid behavior.