Attenuation of surface acoustic waves in a superconducting In/InO sub x film

The attenuation of 530 MHz surface acoustic waves in a superconducting In/InO sub x film is reported as a function of temperature. The shape of the attenuation versus temperature curve shows a sharp drop when the film enters the superconducting state followed by a "tail" which slowly decreases towards zero. Such behavior has also been observed in a superconducting granular lead film. 

In the lead film, the shape of the attenuation curve was qualitatively explained in earlier work using a model based on percolation theory. However, if we compare the attenuation versus temperature data and the resistance versus temperature data of the In/InO sub x film, we find that although the shapes of the two curves are similar, the sharp drop in the attenuation curve occurs at a slightly lower temperature than the sharp drop in the resistance curve.