Abstract
We report measurements of the temperature-dependent anisotropies ( and ) of both the London penetration depth and the upper critical field of . Data for was obtained from measurements of and on a single crystal sample using a tunnel diode oscillator technique. was deduced from field-dependent specific heat measurements on the same sample. and have opposite temperature dependencies, but close to tend to a common value (). These results are in good agreement with theories accounting for the two-gap nature of .
- Received 19 January 2005
DOI:https://doi.org/10.1103/PhysRevLett.95.097005
©2005 American Physical Society