PENETRATION DEPTH MEASUREMENTS FOR ND1.85CE0.15CUO4 AND NBCN THIN-FILMS USING A KINETIC INDUCTANCE TECHNIQUE

The absolute value and the temperature dependence of the magnetic pene tration depth lambda(T) have been measured for high-quality NbCN and N d1.85Ce0.15CuO4 (NCCO) thin films. A kinetic inductance technique was used to measure the screening of a thin superconducting film where the film thickness d was less than or of the order of the London penetrat ion depth. In this limit the kinetic inductance L(k) is proportional t o lambda(2)(T)/d. The kinetic inductance was measured on unpatterned f ilms using a two-coil mutual inductance technique. It was found that t he temperature dependence of the penetration depth for NbCN and NCCO a t low temperatures is exponential as expected, confirming earlier repo rts. We also describe how lambda(O) can be extracted from the kinetic inductance data.