ULTRASONIC-ATTENUATION OF SURFACE ACOUSTIC-WAVES IN SUPERCONDUCTING ZINC

The attenuation of 90-MHz elastic surface waves propagating in both 3 000 and 10 000 films of zinc has been measured as a function of temperature from 3 to 0.38 K. The surface acoustic waves were generated and detected by using a surface-acoustic-wave device with interdigital transducers plated onto a Y-Z cut lithium-niobate substrate. Utilizing the experimental results, in the BCS theory, energy gaps of 2Δ(0) equal to 4.17±0.20 and 3.81±0.20 in units of kBTc were calculated for the 3 000 and 10 000 films, respectively. The transition temperatures for the 3 000 and 10 000 films were 1.5±0.01 and 1.31±0.01 K, respectively. © 1979 The American Physical Society.