Measurement of the Surface Resistance of Superconducting Lead at 2.868 GHz

Abstract

The surface resistance of superconducting lead at 2.868 GHz was determined from a measurement of the unloaded Q of a TE₀₁₁ cavity. The results were compared to the analytical expression for the surface impedance of pure superconductors in the Pippard limit, which was worked out by Abrikosov et al. Adequate agreement was found by writing the reduced surface resistance in the form of r=A r_AGK+r₀, with r₀ being a residual resistance and A a constant. The best fit was obtained for A = 3.0, r₀=2.2×10⁻⁵ and the gap parameter Δ(0)=1.97k_BT_c.