Electrodynamic response of ${\mathrm{Y}}_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_y$ and ${\mathrm{La}}_{1.85}{\mathrm{Sr}}_{0.15}\mathrm{Cu}{\mathrm{O}}_{4-\delta }$ in the superconducting state

Measurements of the temperature dependence of the surface resistance $R_s$ at 9.85 GHz and the screening length ${\delta }_s$ at 1 MHz for the superconducting states of ${\mathrm{Y}}_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_y$ and ${\mathrm{La}}_{1.85}$ ${\mathrm{Sr}}_{0.15}$Cu${\mathrm{O}}_4$ show strong correlations, suggesting that the superconducting state is the same in the two materials. While the overall temperature dependence of $R_s$ is reasonably well described by the Bardeen-Cooper-Schrieffer (BCS) theory in the very dirty limit, additional features are seen in $R_s$ and also in ${\delta }_s$ which suggest detailed deviations from the BCS $s$-wave state.