Surface Impedance of Normal and Superconductors at 24,000 Megacycles per Second

The surface impedance of tin at 24,000 mc/sec. has been investigated in the range of temperatures from 2°K to 300°K, including both the superconducting and normal states, by means of a resonant cavity technique. The experimental techniques are described and the data for the normal state discussed in terms of the theory of the anomalous skin effect given by Reuter and Sondheimer. Agreement is found between the general features of the theory and the data although numerical estimates for the number of free electrons appear to low. The superconducting data are analyzed in terms of a theory which combines the London and the Reuter and Sondheimer theories. The variation of penetration depth, $\lambda$, with temperature is found to be in agreement with other determinations. The best value for ${\lambda }_0$, is estimated at ${10}^{-5\mathrm{}}$ cm.