A METHOD FOR THE ACCURATE MEASUREMENT OF THE COMPLEX CONDUCTIVITY OF HIGH-TC SUPERCONDUCTIVE THIN-FILMS

In this paper, we introduce a method which makes it possible to rapidly and accurately determine the penetration depth as a function of temperature for superconductive thin film samples. A key feature of the approach described here is that it is derived only from electrodynamic definitions and makes no use of a selected model of superconductivity. Another advantage relative to some of the alternative methods presently in use is that it can be expected to give useful results for films with thicknesses that are as much as three times the zero-temperature effective penetration depth. When combined with an accurate evaluation of R(S) as a function of temperature for the same samples, these penetration depth data enable the computation of the complex conductivity for a wide variety of samples. One shortcoming of the method is the fact that it performs well only at temperatures below about 0.95T(c).