Nodeless superconductivity in the infinite-layer electron-doped   Sr_0.9La_0.1CuO_2 cuprate superconductor
  We report on measurements of the in-plane magnetic penetration depth \lambda_{ab} in the infinite-layer electron-doped high-temperature cuprate superconductor Sr_0.9La_0.1CuO_2 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. 
R. Khasanov, A. Shengelaya, A. Maisuradze, D. Di Castro, I.M. Savi\'c,   S. Weyeneth, M.S. Park, D.J. Jang, S.-I. Lee, and H...