UC Irvine

The longitudinal and transverse upper critical magnetic fields Hc2 and Hc2 as a function of temperature T of a single-crystal specimen of the heavy-fermion superconductor UPt3 were measured resistively with the current flowing along the hexagonal c axis. The slope of the linear part of the Hc2 (T) curve near the superconducting transition temperature Tc=0.52 K equals 63 kOe/K, from which a zero-temperature superconducting coherence length 3/401/4120 can be inferred. An analysis using previously reported specific-heat data yields an effective mass ~200 times the free-electron mass and a value of 3/401/4170. The electrical resistivity between Tc and 8 K varies as Tn with n=1.6±0.1. © 1984 The American Physical Society.