Temperature dependence of the penetration depth in ${\mathrm{Nd}}_{1.85}$${\mathrm{Ce}}_{0.15}$${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$ superconducting thin films

Measurements of the in-plane magnetic-field penetration depth for the n-doped high-${\mathit{T}}_{\mathit{c}}$ superconductor ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$ are reported. The measurements were performed at 4 GHz by a microstrip resonator technique on thin films obtained by laser ablation. The temperature dependence of the penetration depth is carefully analyzed and the energy gap-ratio is estimated. The results confirm that ${\mathrm{Nd}}_{1.85}$ ${\mathrm{Ce}}_{0.15}$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{\delta }}$ behaves as a BCS-like superconductor.