Observation of a Schottky Anomaly in the Specific Heat of the Heavy-Fermion Compound UBe ₁₃

Abstract

We present the results of calorimetric measurements of the specific heat in UBe13 and ThBe13 in the temperature range 20 K ≲ T ≲ 120 K. Combined with earlier results of inelastic neutron scattering, the data allow the extraction of the electronic specific heat ΔC in UBe13. ΔC shows a pronounced peak around 70 K which we interpret as a Schottky anomaly due to crystal-field splitting of a 5f3 ground-state configuration. Our results suggest the existence of highly localized 5f electrons in the heavy-fermion compound UBe13.