London penetration depth measurements of the heavy-fermion superconductor

We have measured the London penetration depth $\lambda(T)$ of $\chem{CeCoIn_5}$, a quantum-critical metal where superconductivity arises from a non-Fermi-liquid normal state. Using a tunnel diode oscillator with a novel coil geometry designed to avoid spurious contributions to $\lambda(T)$, we have established the existence of intrinsic and anomalous power law behaviour at low temperature. A systematic analysis raises the possibility that the unusual observations might be due to an extension of quantum criticality into the superconducting state