The effect of the superconducting transition on the acoustic losses in audiofrequency niobium resonators

✍ Scribed by D. G. Blair; J. Ferreirinho

• Publisher: Springer US
• Year: 1980
• Tongue: English
• Weight: 354 KB
• Volume: 41
• Category: Article
• ISSN: 0022-2291
• DOI: 10.1007/bf00117940

✦ Synopsis

The mechanical Q of Nb disk samples has been measured as a function of temperature with different annealing treatments. A rapid increase in Q is seen on cooling through the superconducting transition temperature. This is shown to be consistent with the predictions of the theory of acoustic attenuation due to conduction electrons, and the measurements are believed to be the first audio frequency observation of attenuation by this mechanism. Residual losses in the sample limit the possibility of a quantitative comparison with theory in the superconducting state. Maximum Q values obtained were 1.8 • 10 at 690 Hz, 3.8 x 107 at 1.6 kHz, and 4.8 • 107 at 4.2 kHz. Optimization of the annealing treatment may increase the Q still further, thus enabling improved measurements of the electronic attenuation to be made.