Specific Heat Measurements on a Modulated Quadrupolar Ordering Compound PrPb3at Very Low Temperatures

Abstract

Specific heat of the cubic compound PrPb 3 has been measured at zero field in a temperature range from 0.03 to 2 K. We focused our attention on the electronic state in the antiferroquadrupole (AFQ) phase below the ordering temperature T Q =0.4 K. A large nuclear contribution to the specific heat is observed below ∼50 mK, indicating a nuclear quadrupole splitting due to the symmetry reducing AFQ ordering of 4 f electrons. Subtracting the nuclear contribution from the total specific heat yielded a large T -linear contribution, suggesting a strong mass enhancement of the electronic system in the ground state.