SUPERCONDUCTING AND NORMAL STATE PROPERTIES OF THE HEAVY FERMION COMPOUND PrOs4Sb12

Abstract

The filled skutterudite compound PrOs 4 Sb 12 displays superconductivity with a critical temperature T c ≈ 1.85 K which appears to involve heavy fermion quasiparticles with an effective mass m * ~ 50 - 100 m e as inferred from the slope of the upper critical field curve near T c and the specific heat. New measurements of electrical resistivity ρ(T) in applied magnetic fields, thermoelectric power, and X-ray diffraction are presented. A peak appears in the dρ/dT data for magnetic fields above 4 T that suggests the occurrence of a phase transition in the normal state of PrOs 4 Sb 12 below ~ 1K.