The temperature and field dependence of the effective magnetic penetration depth in the vortex state of a d-wave superconductor, as measured by muon spin rotation experiments, is calculated using a nonlocal London model. We show that at temperatures below T^* \propto \sqrt{B}, the linear T-dependence of the effective penetration depth crosses over to a T^3-dependence. This could provide an explanation for the low temperature flattening of the effective penetration depth curves observed in a recent muon spin rotation experiment.
@article{arxiv.cond-mat/9912196,
title = {Effective "Penetration Depth" in the Vortex State of a d-wave Superconductor},
author = {M. H. S. Amin and M. Franz and Ian Affleck},
journal= {arXiv preprint arXiv:cond-mat/9912196},
year = {2009}
}