Microwave Residual Surface Resistance of Superconductors”

Two distinct models account for the microwave residual surface resistance of superconducting cavities with equally good agreement with the measured temperature and frequency dependence. In presenting his phonon generation model, Passow claimed that Rabinowitz’s fluxoid power loss model of residual resistance does not fit the experimental data, whereas his does. In fact, the two models have essentially the same temperature and frequency dependence. {Submitted to Phys. Rev. ) *Work supported by the U. S. Atomic Energy Commission. An analysis presented by Passowl showed that phonons generated in a superconductor by incident electromagnetic radiation result in a residual power loss with an equivalent surface resistance which agrees well with experimental measurements of temperature and frequency dependence. His expression for surface resistance is