High-frequency losses in tin Josephson tunnel junctions

Abstract

The losses associated with the excitation of surface plasma oscillations in Fiske modes in tin Josephson junctions, at frequencies from 20 to 270 GHz, were measured by studying the currentvoltage characteristics as a function of magnetic field. Our results generally support Economou and Ngai's theory of surface-plasma oscillations and Miller's calculation of the conductivity of superconductors. At lower temperatures, discrepancies that include an anomalous peak in the frequency dependence of the loss may reflect a small disagreement with Miller's results.