Specific heat study on the anomalous normal state of heavy-fermion superconductor PrOs4Sb12

Abstract

The normal state of the Pr-based heavy-fermion superconductor PrOs4Sb12 has been studied by low-temperature specific heat (C) measurements in magnetic fields applied along the 〈100〉 direction using a high-quality single crystal. A pronounced Schottky-like anomaly appearing at ∼2 K in C/T vs T shifts to lower temperatures in applied magnetic fields although the gap-like behavior still remains even at the boundary (∼4.5 T) of the field-induced ordered phase (FIOP). Isothermal field scans for T⩽0.5 K reveal that the electronic specific heat increases progressively with increasing field and has largely enhanced values in the FIOP.