Abstract
We have performed measurements of the surface impedance in the normal and superconducting states of the title compounds in the millimeter wave-frequency range (1–3 ), and have evaluated the complex conductivity for different crystallographic orientations. Above the transition temperature, the materials behave like metals with a scattering rate of approximately 20 . In the superconducting state the electrodynamics is in good agreement with calculations based on a BCS ground state: while the penetration depth and the coherence length are anisotropic, the superconducting energy gap shows no indications of line nodes.
- Received 25 February 1994
DOI:https://doi.org/10.1103/PhysRevB.50.13603
©1994 American Physical Society