Abstract
The surface impedance at 10 GHz was measured systematically in single-crystal for carrier concentrations 0.09≤x≤0.19, from which penetration depth λ was determined. The anisotropy and the depencences on x and temperature T of λ are extensively studied for the first time. The anisotropy of λ(T=0) decreases with increasing x, and still remains larger than 10 for x=0.19. The out-of-plane penetration depth () has a different temperature dependence from the in-plane one (). These results suggest that the electrodynamic properties in the superconducting state along the c axis can be explained by a Josephson-coupled layer model.
- Received 3 March 1993
DOI:https://doi.org/10.1103/PhysRevLett.72.2263
©1994 American Physical Society