The low temperature variation of the London penetration depth for a number of iron-pnictide and iron-chalcogenide superconductors is nearly quadratic, Δλ(T)=βTn with n≈2. The coefficient in this dependence shows a robust scaling, β∝1/Tc3 across different families of these materials. We associate the scaling with a strong pair-breaking. The same mechanism have recently been suggested to explain the scalings of the specific heat jump, ΔC∝Tc3, and of the slopes of the upper critical field, dHc2/dT∝Tc in these materials. This suggests that thermodynamic and electromagnetic properties of the iron-based superconductors can be described within a strong pair-breaking scenario.
@article{arxiv.0912.5346,
title = {London penetration depth and strong pair-breaking in iron-based superconductors},
author = {R. T. Gordon and H. Kim and M. A. Tanatar and R. Prozorov and V. G. Kogan},
journal= {arXiv preprint arXiv:0912.5346},
year = {2010}
}