Break junctions of the heavy-fermion superconductors
  Mechanical-controllable break junctions of the heavy-fermion superconductors can show Josephson-like superconducting anomalies. But a systematic study on the contact size demonstrates that these anomalies are mainly due to Maxwell's resistance being suppressed in the superconducting heavy-fermion phase. Up to day, we could not find any superconducting features by vacuum-tunnelling spectroscopy, providing further evidence for the pair-breaking effect of the heavy-fermion interfaces. 
K. Gloos, F.B. Anders, B. Buschinger, and C. Geibel