We report measurements of the magnetic penetration depth λ in single crystals of CeCoIn5 down to ∼0.14 K using a tunnel-diode-based, self-inductive technique at 28 MHz. While the in-plane penetration depth tends to follow a power law, λ∥∼T3/2, the data are better described as a crossover between linear (T≫T*) and quadratic (T≪T*) behavior, with T* the crossover temperature in the strongr-coupling limit. The c-axis penetration depth λ⊥ is linear in T. Both the magnitude of T* and the different temperature dependencies in the two directions rule out impurity effects, but instead indicate that the penetration depth is governed by nonlocal electrodynamics in a d-wave superconductor with line nodes along the c axis. This is experimental confirmation of directional nonlocality, predicted theoretically by Kosztin and Leggett.
|Original language||English (US)|
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 1 2003|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics