Kinetic inductance in thin superconducting amorphous bismuth films

Abstract

The kinetic inductance of thin superconducting amorphous bismuth films has been measured. In the technique used the film is part of the inductance in the tank-circuit of a 13MHz tunnel diode oscillator. The measured frequency changes are proportional to the square of the BCS temperature dependent super conducting penetration depth. From the temperature dependence of the oscillator frequency we determine a value of the zero degree penetration depth [lambda](o). We also calculate a value of the density of states at the Fermi surface N(o) from [lambda](o) based on the BCS expression for the penetration depth in a "dirty superconductor." These experiments represent the first determination of [lambda](o) and N(o) for an amorphous superconductor.