Abstract
The temperature dependence of the surface resistance , and the penetration depth has been measured in both and directions in . The overall temperature dependences are similar and show a linear behavior at low . This argues against the chains playing a direct role in the unconventional behavior of the surface impedance. The residual of these twin-free crystals is very small, implying a residual conductivity of the order of the minimum value predicted by Lee Phys. Rev. Lett. 71 1837 1993 for a -wave superconductor.
- Received 4 April 1994
DOI:https://doi.org/10.1103/PhysRevLett.73.2484
©1994 American Physical Society