Nodeless superconductivity in the infinite-layer electron-doped cuprate superconductor Sr0.9La0.1CuO2

We report on measurements of the in-plane magnetic penetration depth lambda(ab) in the infinite-layer electron-doped high-temperature cuprate superconductor Sr0.9La0.1CuO2 by means of muon-spin rotation. The observed temperature and magnetic field dependences of lambda(ab) are consistent with the presence of a substantial s-wave component in the superconducting order parameter, in good agreement with the results of tunneling, specific heat, and small-angle neutron scattering experiments.