Abstract
We report specific heat measurements on neutron-irradiated samples, for which the critical temperature is lowered to 8.7 K, but the superconducting transition remains extremely sharp, indicative of a defect structure extremely homogeneous. Our results evidence the presence of two superconducting gaps in the temperature range above 21 K, while single-gap superconductivity is well established as a bulk property, not associated with local disorder fluctuations, when decreases to 11 K.
- Received 22 July 2005
DOI:https://doi.org/10.1103/PhysRevLett.96.077003
©2006 American Physical Society