Penetration depth of electron-doped infinite-layer Sr0.88La0.12CuO2+x thin films

Abstract

The in-plane penetration depth of Sr0.88La0.12CuO2+x thin films at various doping obtained from oxygen reduction has been measured, using ac-susceptibility measurements. For the higher doping samples, the superfluid density deviates strongly from the s-wave behavior, suggesting, in analogy with other electron-doped cuprates, a contribution from a nodal hole pocket, or a small gap on the Fermi surface such as an anisotropic s-wave order parameter. The low value of the superfluid densities, likely due to a strong doping-induced disorder, places the superconducting transition of our samples in the phase-fluctuation regime.