TEMPERATURE-DEPENDENCE OF PENETRATION DEPTH AND SURFACE-RESISTANCE OF ND1.85CE0.15CUO4

The temperature dependence of the in-plane penetration depth lambda(parallel-to) and surface resistance R(s) at 9.6 GHz were measured for high-quality Nd1.85Ce0.15CuO4 thin films and single crystals. Both lambda(parallel-to)(T) and R(s)(T) are well described within the BCS framework over the entire temperature range below T(c), yielding an energy gap ratio 2DELTA/k(B)T(c) = 4.1 +/- 0.2 and the London penetration depth lambda(L parallel-to)(0) is similar to 1000 angstrom. These results indicate that the electrodynamics of this n-type cuprate superconductor are consistent with a single-gap s-wave BCS behavior.